leetcode 4.29

Posted 2020-11-27 wfplingyun

1、202快乐数

class Solution {
public:
    int Sum(int n)
    {
        int res = 0;
        while (n)
        {
            res+= (n % 10) * (n % 10);
            n = n / 10;
        }
        return res;
        
    }
    bool isHappy(int n) {
        unordered_map<int, int>m;
        while (1)
        {
            int res = Sum(n);
            if (res == 1)return true;
            if (m.find(res) != m.end())return false;
            m[res] = 1;
            n = res;

        }
    }
};

2、1095

/**
 * // This is the MountainArray‘s API interface.
 * // You should not implement it, or speculate about its implementation
 * class MountainArray {
 *   public:
 *     int get(int index);
 *     int length();
 * };
 */

class Solution {
public:
    int findtop(MountainArray& mountainArr)
    {
        int low = 0, high = mountainArr.length() - 1;
        int val1 = 0,val2=0,val3=0;
        while (high - low > 1)
        {
            int mid = (low + high) / 2;
            val1 = mountainArr.get(mid);
            val2 = mountainArr.get(mid - 1);

            if(val1 < val2)
            {
                high = mid;
            }
            else
            {
                low = mid;
            }

        }
        return (mountainArr.get(low) > mountainArr.get(high) ? low : high);
    }
    int findindex(MountainArray& mountainArr, int top,int target)
    {
        int low = 0, high = mountainArr.length() - 1, top1 = top;
        int val=0,mid1=0, mid2 =0;
        while (top - 1 > low)
        {
            mid1 = (low + top) / 2;
            val = mountainArr.get(mid1);
            if (val == target)
            {
                return mid1;
            }
            else if (val > target)
            {
                top = mid1;
            }
            else
            {
                low = mid1;
            }
        }
        if (mountainArr.get(low) == target)return low;
        if (mountainArr.get(top) == target)return top;
        while (high-1 > top1)
        {
            mid2 = (high + top1) / 2;
            val = mountainArr.get(mid2);
            if (val== target)
            {
                return mid2;
            }
            else if (val > target)
            {
                top1 = mid2;
            }
            else
            {
                high = mid2;
            }
        }
        if (mountainArr.get(high) == target)return high;
        if (mountainArr.get(top1) == target)return top1;
        return -1;
    } 
    int findInMountainArray(int target, MountainArray& mountainArr) {
        int top = findtop(mountainArr);
        int res = findindex(mountainArr, top, target);
        return res;


    }
};