立志重刷代码随想录60天冲冲冲！！——第二十七天

455. 分发饼干

class Solution {
public:
    int findContentChildren(vector<int>& g, vector<int>& s) {
        sort(g.begin(), g.end());
        sort(s.begin(), s.end());
        int res = 0;
        int startIdx = 0;
        for (int i = 0; i < g.size(); i++) {
            for (int j = startIdx; j < s.size(); j++) {
                if (s[j] >= g[i]) {
                    res++;
                    startIdx = j + 1; // startIdx不能++，应该要赋值j+1！！
                    break;
                }
            }
        }
        return res;
    }
};

376. 摆动序列

class Solution {
public:
    int wiggleMaxLength(vector<int>& nums) {
        int preDiff = 0;
        int curDiff = 0;
        int res = 1; // 默认结尾元素必是满足条件
        for (int i = 0; i < nums.size() - 1; i++) {
            curDiff = nums[i+1] - nums[i];
            if ((preDiff >= 0 && curDiff < 0) || (preDiff <= 0 && curDiff > 0)) {
                res++;
                preDiff = curDiff;
            }
        }
        return res;
    }
};

53. 最大子序和

class Solution {
public:
    // 贪心策略；每次加完nums[i]，若变成负数，则跳转
    int maxSubArray(vector<int>& nums) {
        int sum = 0;
        int maxSum = INT_MIN;
        for (int i = 0; i < nums.size(); i++) {
            sum += nums[i];
            maxSum = max(maxSum, sum);
            if (sum < 0) {
                sum = 0;
            }
        }
        return maxSum;
    }
};