代码随想录算法训练营第31天| 455.分发饼干 376. 摆动序列 53. 最大子序和

今日学习的文章链接，或者视频链接

第八章贪心算法 part01

自己看到题目的第一想法
看完代码随想录之后的想法

455:

class Solution {
public:int findContentChildren(vector<int>& g, vector<int>& s) {sort(g.begin(),g.end());sort(s.begin(),s.end());int g_size = g.size();int s_size = s.size();int result = 0;for(int i = 0,j = 0;i<g_size&&j<s_size;j++){if(g[i]<=s[j]){result++;i++;}}return result;}
};

376

class Solution {
public:int wiggleMaxLength(vector<int>& nums) {int n = nums.size();if (n==1) return 1;int prediff = 0;int curdiff = 0;int result = 1;for(int i =0;i<n-1;i++){curdiff = nums[i+1]-nums[i];if(prediff>=0&&curdiff<0||prediff<=0&&curdiff>0){result++;prediff = curdiff;}}return result;}
};

动态规划：

class Solution {
public:int maxSubArray(vector<int>& nums) {//以 nums[i] 为结尾的「最大子数组和」为 dp[i]int n = nums.size();if(n==0) return 0;vector<int> dp(n);dp[0] = nums[0];int result = dp[0];for(int i=1;i<n;i++){dp[i] = max(nums[i],dp[i-1]+nums[i]);result = max(result,dp[i]);}return result;}
};

贪心：

class Solution {
public:int maxSubArray(vector<int>& nums) {int n = nums.size();if(n==0) return 0;int result = nums[0];int cur = 0;for (int i=0;i<n;i++){cur+=nums[i];if(cur>result){result = cur;}if(cur<0){cur = 0;}}return result;}
};