java codility Max-Counters

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【中文标题】java codility Max-Counters【英文标题】: 【发布时间】:2013-10-28 06:13:49 【问题描述】:

我一直在尝试解决以下任务:

给你 N 个计数器,初始设置为 0,你有两种可能的操作:

    increase(X) − counter X is increased by 1,
    max_counter − all counters are set to the maximum value of any counter.

给出了一个由 M 个整数组成的非空零索引数组 A。这个数组代表连续的操作:

    if A[K] = X, such that 1 ≤ X ≤ N, then operation K is increase(X),
    if A[K] = N + 1 then operation K is max_counter.

例如,给定整数 N = 5 和数组 A,这样:

A[0] = 3
A[1] = 4
A[2] = 4
A[3] = 6
A[4] = 1
A[5] = 4
A[6] = 4

每次连续操作后计数器的值将是:

(0, 0, 1, 0, 0)
(0, 0, 1, 1, 0)
(0, 0, 1, 2, 0)
(2, 2, 2, 2, 2)
(3, 2, 2, 2, 2)
(3, 2, 2, 3, 2)
(3, 2, 2, 4, 2)

目标是计算所有操作后每个计数器的值。

struct Results 
  int * C;
  int L;
; 

写一个函数:

struct Results solution(int N, int A[], int M); 

给定一个整数 N 和一个由 M 个整数组成的非空零索引数组 A,返回一个表示计数器值的整数序列。

序列应返回为:

    a structure Results (in C), or
    a vector of integers (in C++), or
    a record Results (in Pascal), or
    an array of integers (in any other programming language).

例如,给定:

A[0] = 3
A[1] = 4
A[2] = 4
A[3] = 6
A[4] = 1
A[5] = 4
A[6] = 4

该函数应返回 [3, 2, 2, 4, 2],如上所述。

假设:

    N and M are integers within the range [1..100,000];
    each element of array A is an integer within the range [1..N + 1].

复杂性:

    expected worst-case time complexity is O(N+M);
    expected worst-case space complexity is O(N), beyond input storage (not counting the storage required for input arguments).

输入数组的元素可以修改。

这是我的解决方案:

import java.util.Arrays;

class Solution 
    public int[] solution(int N, int[] A) 

        final int condition = N + 1;
        int currentMax = 0;
        int countersArray[] = new int[N];

        for (int iii = 0; iii < A.length; iii++) 
            int currentValue = A[iii];
            if (currentValue == condition) 
                Arrays.fill(countersArray, currentMax);
             else 
                int position = currentValue - 1;
                int localValue = countersArray[position] + 1;
                countersArray[position] = localValue;

                if (localValue > currentMax) 
                    currentMax = localValue;
                
            

        

        return countersArray;
    

这是代码评估: https://codility.com/demo/results/demo6AKE5C-EJQ/

你能告诉我这个解决方案有什么问题吗?

【问题讨论】:

【参考方案1】:

问题出在这段代码上:

for (int iii = 0; iii < A.length; iii++) 
     ...
     if (currentValue == condition) 
         Arrays.fill(countersArray, currentMax);
     
     ...

假设数组A 的每个元素都使用值N+1 进行了初始化。由于函数调用Arrays.fill(countersArray, currentMax) 的时间复杂度为O(N),那么总体而言,您的算法的时间复杂度为O(M * N)。我认为解决此问题的方法不是在调用max_counter 操作时显式更新整个数组A,而是可以将上次更新的值保留为变量。当调用第一个操作(增量)时,您只需查看您尝试增加的值是否大于last_update。如果是,您只需将值更新为 1,否则将其初始化为 last_update + 1。当调用第二个操作时,您只需将last_update 更新为current_max。最后,当您完成并尝试返回最终值时,您再次将每个值与last_update 进行比较。如果它更大,则保留该值,否则返回last_update

class Solution 
    public int[] solution(int N, int[] A) 

        final int condition = N + 1;
        int currentMax = 0;
        int lastUpdate = 0;
        int countersArray[] = new int[N];

        for (int iii = 0; iii < A.length; iii++) 
            int currentValue = A[iii];
            if (currentValue == condition) 
                lastUpdate = currentMax
             else 
                int position = currentValue - 1;
                if (countersArray[position] < lastUpdate)
                    countersArray[position] = lastUpdate + 1;
                else
                    countersArray[position]++;

                if (countersArray[position] > currentMax) 
                    currentMax = countersArray[position];
                
            

        

        for (int iii = 0; iii < N; iii++) 
           if (countersArray[iii] < lastUpdate)
               countersArray[iii] = lastUpdate;
        

        return countersArray;
    

【讨论】:

理论上这听起来是对的,但我还没有尝试过,看看是否能给 100 分 这是假设输入的每个数组都比N小1,可能不是这样? 此解决方案 100% 有效。作为我和其他人的助手,您能否详细说明if (countersArray[position] &lt; lastUpdate) countersArray[position] = lastUpdate + 1; 的逻辑,即用英文术语,为什么您将值设置为lastUpdate + 1,而不是lastUpdate?谢谢 @mils ,假设我们只将position 索引处的计数器设置为lastUpdate。在这种情况下,我们只应用max_counter 操作,而实际上我们已经看到了至少两个操作:max_counterincrease(position + 1)。如果不是后者,我们甚至不会更改此计数器的值,直到 @sve 解决方案中的第二个(也是最后一个)for 循环。 不错的解决方案。我应用你的方法让我的方法达到 100%。我的收获是比较值(有很多 操作)比赋值便宜。每次更新所有计数器的成本太高。答案是跟踪当前最大值和最后一次“扫描”,此时一切都设置为最大值。【参考方案2】:

问题在于,当您获得大量 max_counter 操作时,您会收到大量对 Arrays.fill 的调用,这会使您的解决方案变慢。

您应该保留currentMaxcurrentMin

当您获得max_counter 时,您只需设置currentMin = currentMax。 如果你得到另一个值,我们称之为i: 如果位置i - 1 的值小于或等于currentMin,则将其设置为currentMin + 1。 否则,您将增加它。

最后只需再次遍历计数器数组并将小于currentMin 的所有内容设置为currentMin

【讨论】:

【参考方案3】:

我开发的另一个可能值得考虑的解决方案:http://codility.com/demo/results/demoM658NU-DYR/

【讨论】:

@moda,你介意解释一下你的代码吗?我似乎不明白它是如何完成 maxcounter 任务的。虽然我理解代码,但这种方法非常好,以至于我从来没有想过用这种方式解决它。那么,如果您能解释一下您为什么采用这种方法? “另一个”怎么样? @helpdesk ,考虑阅读上面的@sve 的解决方案。这里B 变量等同于lastUpdate 变量。 这是一个很棒的答案。我将它转换为 swift 4,它又好又干净。实际上,我很惊讶它是多么容易。这节课的说明绝对糟糕。【参考方案4】:

这是这个问题的 100% 解决方案。

// you can also use imports, for example:
// import java.math.*;
class Solution 
    public int[] solution(int N, int[] A) 
        int counter[] = new int[N];
        int n = A.length;
        int max=-1,current_min=0;

        for(int i=0;i<n;i++)
            if(A[i]>=1 && A[i]<= N)
                if(counter[A[i] - 1] < current_min) counter[A[i] - 1] = current_min;
                counter[A[i] - 1] = counter[A[i] - 1] + 1;
                if(counter[A[i] - 1] > max) max = counter[A[i] - 1];
            
            else if(A[i] == N+1)
                current_min = max;
            
        
        for(int i=0;i<N;i++)
            if(counter[i] < current_min) counter[i] =  current_min;
        
        return counter;
    

【讨论】:

【参考方案5】:

我正在添加另一个 Java 100 解决方案,其中包含一些测试用例,它们很有帮助。

// https://codility.com/demo/results/demoD8J6M5-K3T/ 77
// https://codility.com/demo/results/demoSEJHZS-ZPR/ 100
public class MaxCounters 

  // Some testcases
  // (1,[1,2,3]) = [1]
  // (1,[1]) = [1]
  // (1,[5]) = [0]
  // (1,[1,1,1,2,3]) = 3
  // (2,[1,1,1,2,3,1]) = [4,3]
  // (5, [3, 4, 4, 5, 1, 4, 4]) = (1, 0, 1, 4, 1)
  public int[] solution(int N, int[] A) 
      int length = A.length, maxOfCounter = 0, lastUpdate = 0;
      int applyMax = N + 1;
      int result[] = new int[N];

      for (int i = 0; i < length; ++i ) 
          if(A[i] == applyMax)
              lastUpdate = maxOfCounter;
           else if (A[i] <= N)  
              int position = A[i]-1;
              result[position] = result[position] > lastUpdate
                                        ? result[position] + 1 : lastUpdate + 1;
              // updating the max for future use
              if(maxOfCounter <=  result[position]) 
                  maxOfCounter = result[position];
              
          
     
     // updating all the values that are less than the lastUpdate to the max value
     for (int i = 0; i < N; ++i) 
         if(result[i] < lastUpdate) 
             result[i] = lastUpdate;
         
     
     return result;
   

【讨论】:

【参考方案6】:

这是我的 C++ 解决方案,它在代码性上得到了 100。这个概念和上面解释的一样。

int maxx=0;
int lastvalue=0;
void set(vector<int>& A, int N,int X)
    
        for ( int i=0;i<N;i++)
            if(A[i]<lastvalue)
                A[i]=lastvalue;
    

vector<int> solution(int N, vector<int> &A) 
    // write your code in C++11

    vector<int> B(N,0);
    for(unsigned int i=0;i<A.size();i++)
        
            if(A[i]==N+1)
               lastvalue=maxx;

            else
               if(B[A[i]-1]<lastvalue)
                    B[A[i]-1]=lastvalue+1;
                else
                    B[A[i]-1]++;
                if(B[A[i]-1]>maxx)
                    maxx=B[A[i]-1];
            

        
        set(B,N,maxx);
    return B;

【讨论】:

【参考方案7】:
vector<int> solution(int N, vector<int> &A)

    std::vector<int> counters(N);
    auto max = 0;
    auto current = 0;

    for (auto& counter : A)
    
        if (counter >= 1 && counter <= N)
        
            if (counters[counter-1] < max)
                counters[counter - 1] = max;

            counters[counter - 1] += 1;

            if (counters[counter - 1] > current)
                current = counters[counter - 1];
        
        else if (counter > N)
            max = current;

    

    for (auto&& counter : counters)
        if (counter < max)
            counter = max;

    return counters;

【讨论】:

【参考方案8】:

我的 java 解决方案,带有详细解释 100% 正确性,100% 性能:

时间复杂度O(N+M)

 public static int[] solution(int N, int[] A) 

    int[] counters = new int[N];
    //The Max value between all counters at a given time
    int max = 0;

    //The base Max that all counter should have after the "max counter" operation happens
    int baseMax = 0;

    for (int i = 0; i < A.length; i++) 

        //max counter Operation ==> updating the baseMax
        if (A[i] > N) 
            // Set The Base Max that all counters should have
            baseMax = max;

        

        //Verify if the value is bigger than the last baseMax because at any time a "max counter" operation can happen and the counter should have the max value
        if (A[i] <= N && counters[A[i] - 1] < baseMax) 
            counters[A[i] - 1] = baseMax;
        

        //increase(X) Operation => increase the counter value
        if (A[i] <= N) 
            counters[A[i] - 1] = counters[A[i] - 1] + 1;

            //Update the max
            max = Math.max(counters[A[i] - 1], max);
        
    

    //Set The remaining values to the baseMax as not all counters are guaranteed to be affected by an increase(X) operation in "counters[A[i] - 1] = baseMax;"
    for (int j = 0; j < N; j++) 
        if (counters[j] < baseMax)
            counters[j] = baseMax;
    

    return counters;

【讨论】:

【参考方案9】:
  vector<int> solution(int N, vector<int> &A) 

    std::vector<int> counter(N, 0); 
    int max = 0;
    int floor = 0;

    for(std::vector<int>::iterator i = A.begin();i != A.end(); i++)
    
        int index = *i-1;
        if(*i<=N && *i >= 1)
        
            if(counter[index] < floor)
              counter[index] = floor;
            counter[index] += 1;
            max = std::max(counter[index], max);
        
        else
        
            floor = std::max(max, floor);
        
    
    for(std::vector<int>::iterator i = counter.begin();i != counter.end(); i++)
    
       if(*i < floor)
         *i = floor;
    
    return counter;

【讨论】:

【参考方案10】:

Hera 是我的 AC Java 解决方案。这个想法和@Inwvr解释的一样:

public int[] solution(int N, int[] A) 
        int[] count = new int[N];
        int max = 0;
        int lastUpdate = 0;
        for(int i = 0; i < A.length; i++)
            if(A[i] <= N)
                if(count[A[i]-1] < lastUpdate)
                    count[A[i]-1] = lastUpdate+1;   
                
                else
                    count[A[i]-1]++;
                    
                max = Math.max(max, count[A[i]-1]);
            
            else
                lastUpdate = max;   
            
          
        for(int i = 0; i < N; i++)
            if(count[i] < lastUpdate)
                count[i] = lastUpdate;
            
        return count;
    

【讨论】:

【参考方案11】:

在上面的帮助下,我在 php 中获得了 100 分

function solution($N, $A) 
    $B = array(0);
    $max = 0;

    foreach($A as $key => $a) 
        $a -= 1;
        if($a == $N) 
            $max = max($B);
         else 
            if(!isset($B[$a])) 
                $B[$a] = 0;
            

            if($B[$a] < $max) 
                $B[$a] = $max + 1;
             else 
                $B[$a] ++;
            

        

    

    for($i=0; $i<$N; $i++) 
        if(!isset($B[$i]) || $B[$i] < $max) 
            $B[$i] = $max;
        

    

    return $B;



【讨论】:

【参考方案12】:

这是该问题的另一种 C++ 解决方案。

理由总是一样的。

    避免在指令 2 时将所有计数器设置为最大计数器,因为这会将复杂度提高到 O(N*M)。 等到我们在单个计数器上获得另一个操作代码。 此时算法会记住它是否遇到了 max_counter 并因此设置计数器值。

代码如下:

vector<int> MaxCounters(int N, vector<int> &A) 

    vector<int> n(N, 0);
    int globalMax = 0;
    int localMax = 0;

    for( vector<int>::const_iterator it = A.begin(); it != A.end(); ++it)
    
        if ( *it >= 1 && *it <= N)
        
            // this is an increase op.
            int value = *it - 1;
            n[value] = std::max(n[value], localMax ) + 1;
            globalMax = std::max(n[value], globalMax);
        
        else
        
            // set max counter op.
            localMax = globalMax;
        
    

    for( vector<int>::iterator it = n.begin(); it != n.end(); ++it)
        *it = std::max( *it, localMax );

    return n;

【讨论】:

【参考方案13】:

100%,O(m+n)

public int[] solution(int N, int[] A) 

    int[] counters = new int[N];
    int maxAIs = 0;
    int minAShouldBe = 0;

    for(int x : A) 
        if(x >= 1 && x <= N) 
            if(counters[x-1] < minAShouldBe) 
                counters[x-1] = minAShouldBe;
            

            counters[x-1]++;

            if(counters[x-1] > maxAIs) 
                maxAIs = counters[x-1];
            
         else if(x == N+1) 
            minAShouldBe = maxAIs;
        
    

    for(int i = 0; i < N; i++) 
        if(counters[i] < minAShouldBe) 
            counters[i] = minAShouldBe;
        
    

    return counters;

【讨论】:

【参考方案14】:

这是我的代码,但它的 88% 原因是 10000 个元素需要 3.80 秒而不是 2.20 秒

类解决方案

boolean maxCalled;

public int[] solution(int N, int[] A) 

int max =0;
int [] counters = new int [N];
    int temp=0;
    int currentVal = 0;
    for(int i=0;i<A.length;i++)
    currentVal = A[i];
    if(currentVal <=N)
        temp = increas(counters,currentVal);
        if(temp > max)
        max = temp;
        
    else
        if(!maxCalled)
        maxCounter(counters,max);
    

    

    return counters;




int increas (int [] A, int x)  
 maxCalled = false;
 return ++A[x-1];  
 //return t;


void maxCounter (int [] A, int x)
 maxCalled = true;
  for (int i = 0; i < A.length; i++) 
 A[i] = x;
  


【讨论】:

【参考方案15】:

Arrays.fill() 在数组交互中调用使程序 O(N^2)

Here 是一个可能的解决方案,它的运行时间为 O(M+N)。

想法是——

    对于第二个操作,跟踪通过增量获得的最大值,这是我们在当前迭代之前的基础值,任何值都不能小于这个。

    对于第一次操作,如果需要,在增量之前将值重置为基值。

    public static int[] 解决方案(int N, int[] A) int counters[] = new int[N];

    int base = 0;
    int cMax = 0;
    
    for (int a : A) 
        if (a > counters.length) 
            base = cMax;
         else 
            if (counters[a - 1] < base) 
                counters[a - 1] = base;
            
    
            counters[a - 1]++;
    
            cMax = Math.max(cMax, counters[a - 1]);
        
    
    
    for (int i = 0; i < counters.length; i++) 
        if (counters[i] < base) 
            counters[i] = base;
        
    
    
    return counters;
    

【讨论】:

【参考方案16】:

按照我在 JAVA (100/100) 中的解决方案。

public boolean isToSum(int value, int N) 
    return value >= 1 && value <= N;


public int[] solution(int N, int[] A) 
    int[] res = new int[N];
    int max =0;
    int minValue = 0;

    for (int i=0; i < A.length; i++)
        int value = A[i];
        int pos = value -1;
        if ( isToSum(value, N)) 
            if( res[pos] < minValue) 
                res[pos] = minValue;
            
            res[pos] += 1;
            if (max < res[pos]) 
                max = res[pos];
            
         else 
            minValue = max;
        
    

    for (int i=0; i < res.length; i++)
        if ( res[i] < minValue )
            res[i] = minValue;
        
    
    return res;

【讨论】:

【参考方案17】:

我的解决方案是:

public class Solution   

        public int[] solution(int N, int[] A) 

            int[] counters = new int[N];
            int[] countersLastMaxIndexes = new int[N];
            int maxValue = 0;
            int fixedMaxValue = 0;
            int maxIndex = 0;
            for (int i = 0; i < A.length; i++) 
                if (A[i] <= N) 
                    if (countersLastMaxIndexes[A[i] - 1] != maxIndex) 
                        counters[A[i] - 1] = fixedMaxValue;
                        countersLastMaxIndexes[A[i] - 1] = maxIndex;

                    
                    counters[A[i] - 1]++;
                    if (counters[A[i] - 1] > maxValue) 
                        maxValue = counters[A[i] - 1];
                    
                 else 
                    maxIndex = i;
                    fixedMaxValue = maxValue;
                

            
            for (int i = 0; i < countersLastMaxIndexes.length; i++) 
                if (countersLastMaxIndexes[i] != maxIndex) 
                    counters[i] = fixedMaxValue;
                    countersLastMaxIndexes[i] = maxIndex;
                
            

            return counters;
        

【讨论】:

【参考方案18】:

在我的 Java 解决方案中,我仅在需要时更新了解决方案 [] 中的值。最后用正确的值更新了解决方案[]。

public int[] solution(int N, int[] A) 
    int[] solution = new int[N];
    int maxCounter = 0;
    int maxCountersSum = 0;
    for(int a: A) 
        if(a >= 1 && a <= N) 
            if(solution[a - 1] < maxCountersSum)
                solution[a - 1] = maxCountersSum;
            solution[a - 1]++;
            if(solution[a - 1] > maxCounter)
                maxCounter = solution[a - 1];
        
        if(a == N + 1) 
            maxCountersSum = maxCounter;
        
    
    for(int i = 0; i < N; i++) 
        if(solution[i] < maxCountersSum)
            solution[i] = maxCountersSum;
    

    return solution;

【讨论】:

【参考方案19】:

这是我的 python 解决方案:

def solution(N, A):
    # write your code in Python 3.6
    RESP = [0] * N
    MAX_OPERATION = N + 1
    current_max = 0
    current_min = 0
    for operation in A:
        if operation != MAX_OPERATION:
            if RESP[operation-1] <= current_min:
                RESP[operation-1] = current_min + 1
            else:
                RESP[operation-1] += 1

            if RESP[operation-1] > current_max:
                current_max = RESP[operation-1]
        else:
            if current_min == current_max:
                current_min += 1
            else:
                current_min = current_max

    for i, val in enumerate(RESP):
        if val < current_min:
            RESP[i] = current_min
    return RESP

【讨论】:

【参考方案20】:
def sample_method(A,N=5):
    initial_array = [0,0,0,0,0]
for i in A:

    if(i>=1):
      if(i<=N):
        initial_array[i-1]+=1
      else:
        for a in range(len(initial_array)):
          initial_array[a]+=1
    print i
    print initial_array

【讨论】:

尝试对您的解决方案进行小幅评价 对您的解决方案进行简短说明会有所帮助。【参考方案21】:

这是我使用 python 3.6 的解决方案。结果是 100% 的正确性,但 40% 的性能(其中大部分是因为超时)。仍然无法弄清楚如何优化此代码,但希望有人能发现它有用。

def solution(N, A):
    count = [0]*(N+1)
    for i in range(0,len(A)):
        if A[i] >=1 and A[i] <= N:
            count[A[i]] += 1
        elif A[i] == (N+1): 
            count = [max(count)] * len(count)
    count.pop(0)
    return count

【讨论】:

【参考方案22】:

打字稿:

function counters(numCounters: number, operations: number[]) 
const counters = Array(numCounters)

let max = 0
let currentMin = 0

for (const operation of operations) 
    if (operation === numCounters + 1) 
        currentMin = max
     else 
        if (!counters[operation - 1] || counters[operation - 1] < currentMin) 
            counters[operation - 1] = currentMin
        

        counters[operation - 1] = counters[operation - 1] + 1

        if (counters[operation - 1] > max) 
            max += 1
        
    


for (let i = 0; i < numCounters; i++) 
    if (!counters[i] || counters[i] < currentMin) 
        counters[i] = currentMin
    


return counters

console.log(solution=$counters(5, [3, 4, 4, 6, 1, 4, 4]))

【讨论】:

【参考方案23】:

100 分 javascript 解决方案,包括性能改进以忽略重复的 max_counter 迭代:

function solution(N, A) 
    let max = 0;
    let counters = Array(N).fill(max);
    let maxCounter = 0;

    for (let op of A) 
        if (op <= N && op >= 1) 
            maxCounter = 0;
            if (++counters[op - 1] > max) 
                max = counters[op - 1];
            
         else if(op === N + 1 && maxCounter === 0) 
            maxCounter = 1;
            for (let i = 0; i < counters.length; i++) 
                counters[i] = max;   
            
        
    

    return counters;

【讨论】:

【参考方案24】:

JAVA 中的解决方案 (100/100)

    class Solution 
    public int[] solution(int N, int[] A) 
        // write your code in Java SE 8
        int[] result = new int[N];
        int base = 0;
        int max = 0;
        int needToChange=A.length;;
        for (int k = 0; k < A.length; k++) 
            int X = A[k];
            if (X >= 1 && X <= N) 

                if (result[X - 1] < base) 
                    result[X - 1] = base;
                
                result[X - 1]++;
                if (max < result[X - 1]) 
                    max = result[X - 1];
                
            
            if (X == N + 1) 
                base = max;
                needToChange= X-1;

            
        
        for (int i = 0; i < needToChange; i++) 
            if (result[i] < base) 
                result[i] = base;
            
        
        return result;

    


【讨论】:

【参考方案25】:

我的 Java 解决方案。它提供 100% 但很长(相比之下)。我使用 HashMap 来存储计数器。

检测到的时间复杂度:O(N + M)

import java.util.*;

class Solution 
  final private Map<Integer, Integer> counters = new HashMap<>();
  private int maxCounterValue = 0;
  private int maxCounterValueRealized = 0;

  public int[] solution(int N, int[] A) 
    if (N < 1) return new int[0];

    for (int a : A) 
      if (a <= N) 
        Integer current = counters.putIfAbsent(a, maxCounterValueRealized + 1);
        if (current == null) 
          updateMaxCounterValue(maxCounterValueRealized + 1);
         else 
          ++current;
          counters.replace(a, current);
          updateMaxCounterValue(current);
        
       else 
        maxCounterValueRealized = maxCounterValue;
        counters.clear();
      
    

    return getCountersArray(N);
  

  private void updateMaxCounterValue(int currentCounterValue) 
    if (currentCounterValue > maxCounterValue)
      maxCounterValue = currentCounterValue;
  

  private int[] getCountersArray(int N) 
    int[] countersArray = new int[N];

    for (int j = 0; j < N; j++) 
      Integer current = counters.get(j + 1);
      if (current == null) 
        countersArray[j] = maxCounterValueRealized;
       else 
        countersArray[j] = current;
      
    

    return countersArray;
  

【讨论】:

【参考方案26】:

这是 100 % 的 python 解决方案 Codility Max counter 100%

def solution(N, A):
"""
Solution at 100% - https://app.codility.com/demo/results/trainingUQ95SB-4GA/
Idea is first take the counter array of given size N
take item from main A one by one + 1 and put in counter array , use item as index
keep track of last max operation
at the end replace counter items with max of local or counter item it self
:param N:
:param A:
:return:
"""
global_max = 0
local_max = 0
# counter array
counter = [0] * N

for i, item in enumerate(A):
    # take item from original array one by one - 1 - minus due to using item as index
    item_as_counter_index = item - 1
    # print(item_as_counter_index)
    # print(counter)
    # print(local_max)
    # current element less or equal value in array and greater than 1
    #         if A[K] = X, such that 1 ≤ X ≤ N, then operation K is increase(X),
    if N >= item >= 1:
        # max of local_max counter at item_as_counter_index
        # increase counter array value and put in counter array
        counter[item_as_counter_index] = max(local_max, counter[item_as_counter_index]) + 1
        # track the status of global_max counter so far
        # this is operation K
        global_max = max(global_max, counter[item_as_counter_index])
    #         if A[K] = N + 1 then operation K is max counter.
    elif item == N + 1:
        # now operation k is as local max
        # here we need to replace all items in array with this global max
        # we can do using for loop for array length but that will cost bigo n2 complexity
        # example -  for i, item in A: counter[i] = global_max
        local_max = global_max
    # print("global_max each step")
    # print(global_max)

# print("local max so far....")
# print(local_max)
# print("counter - ")
# print(counter)
# now counter array - replace all elements which are less than the local max found so far
# all counters are set to the maximum value of any counter
for i, item in enumerate(counter):
    counter[i] = max(item, local_max)

return counter

结果 = 解决方案(1, [3, 4, 4, 6, 1, 4, 4]) print("Sol" + str(结果))

【讨论】:

【参考方案27】:

enter link description here

使用 O ( N + M ) 获得 100% 的结果

class Solution 
public int[] solution(int N, int[] A) 
    // write your code in Java SE 8

    int max = 0;
    int[] counter = new int[N];
    int upgrade = 0;

    for ( int i = 0; i < A.length; i++ )
    
        if ( A[i] <= N )
        
            if ( upgrade > 0 && upgrade > counter[A[i] - 1 ] )
            
                counter[A[i] - 1] = upgrade; 
            

            counter[A[i] - 1 ]++;

            if ( counter[A[i] - 1 ] > max )
                
                    max = counter[A[i] - 1 ];
                
        
        else
        
            upgrade = max;
        

    

    for ( int i = 0; i < N; i++ )
    
        if ( counter[i] < upgrade)
        
            counter[i] = upgrade;
        
    

    return counter;


【讨论】:

【参考方案28】:

Java 100%/100%,无导入


public int[] solution(int N, int[] A) 

    int[] counters = new int[N];

    int currentMax = 0;
    int sumOfMaxCounters = 0;
    boolean justDoneMaxCounter = false;

    for (int i = 0; i < A.length ; i++) 

        if (A[i]  <= N) 

            justDoneMaxCounter = false;
            counters[A[i]-1]++;
            currentMax = currentMax < counters[A[i]-1] ? counters[A[i]-1] : currentMax;

        else if (!justDoneMaxCounter)

            sumOfMaxCounters += currentMax;     
            currentMax = 0;
            counters = new int[N];
            justDoneMaxCounter = true;

        
    


    for (int j = 0; j < counters.length; j++) 
        counters[j] = counters[j] + sumOfMaxCounters;
    

    return counters;

【讨论】:

您好,感谢您在 *** 上发表的第一篇文章。如果您不仅要发布代码,还要解释您更改具体内容的内容和原因,如果您想得到好的答案,那就太好了。【参考方案29】:

python 解决方案:100% 100%

def solution(N, A):
    c = [0] * N

    max_element = 0
    base = 0
    for item in A:

        if item >= 1 and N >= item:
            c[item-1] = max(c[item-1], base) + 1
            max_element = max(c[item - 1], max_element)
        elif item == N + 1:
            base = max_element

    for i in range(N):
        c[i] = max (c[i], base)
    return c
    pass

【讨论】:

【参考方案30】:

使用 applyMax 记录最大操作数

时间复杂度: O(N + M)

class Solution 
    public int[] solution(int N, int[] A) 
        // write your code in Java SE 8
        
        int max = 0, applyMax = 0;;
        int[] result = new int[N];
        
        for (int i = 0; i < A.length; ++i) 
            int a = A[i];
            
            if (a == N + 1) 
                applyMax = max;
            
            
            if (1 <= a && a <= N) 
                result[A[i] - 1] = Math.max(applyMax, result[A[i] - 1]);
                max = Math.max(max, ++result[A[i] - 1]);
            
        
        
        for (int i = 0; i < N; ++i) 
            if (result[i] < applyMax) 
                result[i] = applyMax;
            
        
        
        return result;
    

【讨论】:

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