Leetcode 雙週賽題目（任意子數組和的絕對值的最大值以及刪除字符串兩端相同字符後的最短長度）

同時維護當前下標的數組的最大值和最小值即可。

class Solution {
public:
    int maxAbsoluteSum(vector<int>& nums) {
        int n = nums.size();
        if(n==0) return 0;
        vector<int> maxSum(n);
        vector<int> minSum(n);
        int res = abs(nums[0]);
        maxSum[0] = nums[0], minSum[0] = nums[0];
        for(int i=1;i<n;i++){
            maxSum[i] = max(nums[i],maxSum[i-1]+nums[i]);
            minSum[i] = min(nums[i],minSum[i-1]+nums[i]);
            res = max(res,max(abs(maxSum[i]),abs(minSum[i])));
        }
        return res;
    }
};

純模擬題目 

class Solution {
public:
    int minimumLength(string s) {
        int i = 0, j = s.size()-1;
        while(i<j&&s[i]==s[j]){
            while(i+1<j&&s[i]==s[i+1]) i++;
            while(j-1>i&&s[j]==s[j-1]) j--;
            i++;
            j--;
        }
        return j-i+1;
    }
};