2021/8/25

leetcode3题

重新学习了下红黑树 平衡二叉树 堆

mysql 5讲

两篇面经学习

今天状态不是很好

```
//笔记将同步在小程序中，便于复
class Solution {
public:
    int trap(vector<int>& height) {
        int area = 0,pre = 0,ans = 0;
       for(int i = 1; i < height.size(); i ++){
          if(height[i] >= height[pre]) {
              ans = ans + area;
              pre = i;
              area = 0;
              continue;
          }
          area += height[pre] - height[i];
          
       }
       area = 0; pre = height.size() - 1;
       for(int i = height.size() - 2; i >= 0; i --){
          if(height[i] > height[pre]) {
              ans = ans + area;
              pre = i;
              area = 0;
              continue;
          }
          area += height[pre] - height[i];
       }
       return ans;
    }
};
```

　　

class Solution {
public:
    int dp[550][550] = {0};
    int minDistance(string word1, string word2) {
        for(int i = 0; i <= word2.size(); i ++){
            dp[0][i] = i;
        }
        for(int i = 0; i <= word1.size(); i ++){
            dp[i][0] = i;
        }
        for(int i = 1; i <= word1.size(); i ++){
            for(int j = 1; j <= word2.size(); j ++){
                if(word1[i - 1] == word2[j - 1]){
                    dp[i][j] = min(dp[i - 1][j - 1],min(dp[i - 1][j] + 1,dp[i][j - 1] + 1));
                } else {
                    dp[i][j] = min(dp[i - 1][j - 1] + 1,min(dp[i - 1][j] + 1,dp[i][j - 1] + 1));
                }
            }
        }
        return dp[word1.size()][word2.size()];
    }
};