Edit Distance in Leetcode

72. 编辑距离

class Solution {
public:
    /* 非递归方式 
    int minDistance(string word1, string word2) {
        if(word1.size()==0)
            return word2.size();
        if(word2.size()==0)
            return word1.size();
        
        int m = word1.size();
        int n = word2.size();
        //初始化赋值
        int dp[m+1][n+1] = {0};
        for(int i=0;i<=m;++i)
            dp[i][0]=i;
        for(int i=0;i<=n;++i)
            dp[0][i]=i;
        
        int aux;
        for(int i=1; i<=m;++i)
        {
            for(int j=1;j<=n;++j)
            {
                if(word1[i-1]==word2[j-1])
                    dp[i][j] = dp[i-1][j-1];
                else
                {
                    dp[i][j] = min(min(dp[i-1][j], dp[i][j-1]),dp[i-1][j-1])+1;
                }
            }
        }
        return dp[m][n];
    }*/
    //递归+记录
    string w1;
    string w2;
    int search(int idx1, int idx2, vector<vector<int>>&dp)
    {
        if(idx1 < 0)
            return idx2+1;
        
        if(idx2 < 0)
            return idx1+1;
        
        int a, b, c;
        
        if(dp[idx1][idx2] > 0)
            return dp[idx1][idx2];
        
        if(w1[idx1] == w2[idx2])
        {
            a = search(idx1-1, idx2-1, dp);
            b = 10000000;
            c = 10000000;
        }
        else
        {
            a = search(idx1-1, idx2-1, dp) + 1;
            b = search(idx1-1, idx2, dp) + 1;
            c = search(idx1, idx2-1, dp) + 1;
        }
        dp[idx1][idx2] = min(min(a,b),c);
        cout << dp[idx1][idx2]<< endl;
        return dp[idx1][idx2];
    }
    
    int minDistance(string word1, string word2) {
        if(word1.size()==0)
            return word2.size();
        if(word2.size()==0)
            return word1.size();
        w1=word1;
        w2=word2;
        int m=word1.size();
        int n=word2.size();
        vector<vector<int>> dp(m, vector<int>(n,0));
        return search(word1.size()-1, word2.size()-1, dp);
    }
    
};