LeetCode-in-Go
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
func minDistance(word1 string, word2 string) int {
n1 := len(word1)
n2 := len(word2)
if n2 > n1 {
return minDistance(word2, word1)
}
dp := make([]int, n2+1)
for j := 0; j <= n2; j++ {
dp[j] = j
}
for i := 1; i <= n1; i++ {
prev := dp[0]
dp[0] = i
for j := 1; j <= n2; j++ {
temp := dp[j]
if word1[i-1] != word2[j-1] {
dp[j] = 1 + min(prev, min(dp[j], dp[j-1]))
} else {
dp[j] = prev
}
prev = temp
}
}
return dp[n2]
}
func min(x, y int) int {
if x < y {
return x
}
return y
}