codechef AUG17 T1 Chef and Rainbow Array

Posted 2020-10-01 友人A

Chef and Rainbow Array Problem Code: RAINBOWA  

Chef likes all arrays equally. But he likes some arrays more equally than others. In particular, he loves Rainbow Arrays.

An array is Rainbow if it has the following structure:

• First a₁ elements equal 1.
• Next a₂ elements equal 2.
• Next a₃ elements equal 3.
• Next a₄ elements equal 4.
• Next a₅ elements equal 5.
• Next a₆ elements equal 6.
• Next a₇ elements equal 7.
• Next a₆ elements equal 6.
• Next a₅ elements equal 5.
• Next a₄ elements equal 4.
• Next a₃ elements equal 3.
• Next a₂ elements equal 2.
• Next a₁ elements equal 1.
• a_i can be any non-zero positive integer.
• There are no other elements in array.

Help Chef in finding out if the given array is a Rainbow Array or not.

Input

• The first line of the input contains an integer T denoting the number of test cases.
• The first line of each test case contains an integer N, denoting the number of elements in the given array.
• The second line contains N space-separated integers A₁, A₂, ..., A_N denoting the elements of array.

Output

• For each test case, output a line containing "yes" or "no" (without quotes) corresponding to the case if the array is rainbow array or not.

Constraints

• 1 ≤ T ≤ 100
• 7 ≤ N ≤ 100
• 1 ≤ A_i ≤ 10

Subtasks

• Subtask 1 (100 points) : Original constraints

Example

Input
3
19
1 2 3 4 4 5 6 6 6 7 6 6 6 5 4 4 3 2 1
14
1 2 3 4 5 6 7 6 5 4 3 2 1 1
13
1 2 3 4 5 6 8 6 5 4 3 2 1

Output
yes
no
no

Explanation

The first example satisfies all the conditions.

The second example has 1 element of value 1 at the beginning and 2 elements of value 1 at the end.

The third one has no elements with value 7 after elements with value 6.

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cc暂时没给中文翻译 所以只好搬英文辣

不然我简述一下题意吧

就是要判断一个序列是否只出现并且都出现了1-7

还要求是个回文串并且只有一个峰（也就是单峰）

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int inf=0x3f3f3f3f;
int read(){
    int ans=0,f=1,c=getchar();
    while(c<‘0‘||c>‘9‘){if(c==‘-‘) f=-1; c=getchar();}
    while(c>=‘0‘&&c<=‘9‘){ans=ans*10+(c-‘0‘); c=getchar();}
    return ans*f;
}
int T,n,s[257],c[257];
int main()
{
    T=read();
    while(T--){
        bool f=false;
        memset(c,0,sizeof(c));
        n=read(); 
        for(int i=1;i<=n;i++){
            s[i]=read();
            if(s[i]>7||s[i]<1) f=1;
            else c[s[i]]=1;
        }
        for(int i=1;i<=7;i++) if(!c[i]) f=1;
        if(f){printf("no\n"); continue;}
        int cnt=(n+1)/2;
        s[0]=-inf; s[n+1]=-inf;
        for(int i=1,j=n;i<=cnt;i++,j--) 
            if(s[i]!=s[j]||s[i]<s[i-1]||s[j]<s[j+1]){
                printf("no\n"); 
                f=1;
                break;
            }
        if(!f) printf("yes\n");
    }
    return 0;
}

View Code