算法

(动态规划) $O(n^2)$

原来是这样一回事，之前没怎么明白为啥直接 if bar == foo;
原来只是枚举所有情况

C++ 代码

class Solution {
public:
    int minDistance(string word1, string word2) {
        int n = word1.size();
        int m = word2.size();
        vector<vector<int>> dp(n + 1, vector<int> (m + 1, 0x3f3f3f3f));
        dp[0][0] = 0;
        for (int i = 0; i <= n; ++i) {
            dp[i][0] = i;
        }
        for (int j = 0; j <= m; ++j) {
            dp[0][j] = j;
        }
        for (int i = 1; i <= n; ++i) {
            for (int j = 1; j <= m; ++j) {
                dp[i][j] = min(dp[i][j], dp[i][j - 1] + 1);
                dp[i][j] = min(dp[i][j], dp[i - 1][j] + 1);
                dp[i][j] = min(dp[i][j], dp[i - 1][j - 1] + (word1[i - 1] != word2[j - 1]));
            } 
        }
        return dp[n][m];
    }
};