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72. Edit Distance
Hard
Given two strings word1 and word2, return the minimum number of operations required to convert word1 to word2.
You have the following three operations permitted on a word:
- Insert a character
- Delete a character
- Replace a character
Example 1:
Input: word1 = “horse”, word2 = “ros”
Output: 3
Explanation: horse -> rorse (replace ‘h’ with ‘r’) rorse -> rose (remove ‘r’) rose -> ros (remove ‘e’)
Example 2:
Input: word1 = “intention”, word2 = “execution”
Output: 5
Explanation: intention -> inention (remove ‘t’) inention -> enention (replace ‘i’ with ‘e’) enention -> exention (replace ‘n’ with ‘x’) exention -> exection (replace ‘n’ with ‘c’) exection -> execution (insert ‘u’)
Constraints:
0 <= word1.length, word2.length <= 500word1andword2consist of lowercase English letters.
Solution
public class Solution {
public int MinDistance(string word1, string word2) {
var map = new int[word1.Length + 1, word2.Length + 1];
for (int i = 0; i <= word1.Length; i++) {
map[i, 0] = i;
}
for (int i = 0; i <= word2.Length; i++) {
map[0, i] = i;
}
for (int i = 1; i <= word1.Length; i++) {
for (var j = 1; j <= word2.Length; j++) {
var add = word1[i - 1] == word2[j - 1] ? 0 : 1;
var min = Math.Min(map[i - 1, j] + 1, map[i, j - 1] + 1);
map[i, j] = Math.Min(min, map[i - 1, j - 1] + add);
}
}
return map[word1.Length, word2.Length];
}
}