Edit Distance

Edit Distance

Given two words word1 and word2, find the minimum number of steps required to convert word1 to word2. (each operation is counted as 1 step.)

You have the following 3 operations permitted on a word:

a) Insert a character
b) Delete a character
c) Replace a character

class Solution {
public:
    int minDistance(string word1, string word2) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        int n1 = word1.size();
        int n2 = word2.size();
        
        if (n1 == 0) {
            return n2;
        }
        else if (n2 == 0) {
            return n1;
        }
        
        vector >dp;
        dp.resize(n1 + 1);
        for (int i = 0; i <= n1; ++i) {
            dp[i].resize(n2 + 1);
        }
        
        for (int i = 0; i <= n1; ++i) {
            dp[i][0] = i;
        }
        for (int j = 1; j <= n2; ++j) {
            dp[0][j] = j;
        }
        
        for (int i = 1; i <= n1; ++i) {
            for (int j = 1; j <= n2; ++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]) + 1,
                        dp[i-1][j-1] + 1);
                }
            }
        }
        
        return dp[n1][n2];
    }
};