【Lintcode】119.Edit Distance

题目：

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:

• Insert a character
• Delete a character
• Replace a character

Example

Given word1 = "mart" and word2 = "karma", return 3.

题解：

Solution 1 ()

class Solution {
public:
    int minDistance(string word1, string word2) {
        int len1 = word1.size(), len2 = word2.size();
        vector<vector<int> > dp(len1 + 1, vector<int> (len2 + 1));
        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] = min(dp[i - 1][j - 1], min(dp[i - 1][j], dp[i][j - 1])) + 1;
                }
            }
        }
        return dp[len1][len2];
    }
};