leetcode - 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(std::string word1, std::string word2) {int len1 = word1.size(),len2 = word2.size();if(len1 == 0 || len2 == 0) return std::max(len1,len2);        std::vector<std::vector<int>> dp(len1+1,std::vector<int>(len2+1,0));for (int i = 0; i <= len1; i++){dp[i][0] = i;}for (int i = 0; i <= len2; i++){dp[0][i] = i;}for (int i = 1; i <= len1; i++){for (int j = 1; j <= len2; j++){if(word1[i-1] == word2[j-1]){dp[i][j] = dp[i-1][j-1];}else{dp[i][j] = std::min(dp[i-1][j-1],std::min(dp[i-1][j],dp[i][j-1])) + 1;}}}return dp[len1][len2];    }};