Introduction Link to heading
Given two words word1 and word2, find the minimum number of operations required to convert word1 to word2.
You have the following 3 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')
Solution Link to heading
Let’s use DP with mutations count in cell.
func minDistance(word1 string, word2 string) int {
n, m := len(word1), len(word2)
dp := make([][]int, n+1)
dp[0] = make([]int, m+1)
for j := 1; j <= m; j++ {
dp[0][j] = j
}
for i := 1; i <= n; i++ {
dp[i] = make([]int, m+1)
dp[i][0] = i
for j := 1; j <= m; j++ {
cost := 0
if word1[i-1] != word2[j-1] {
cost = 1
}
dp[i][j] = min(dp[i-1][j] + 1, dp[i][j-1] + 1, dp[i-1][j-1] + cost)
}
}
return dp[n][m]
}
func min(a, b, c int) int {
if a > b {
a = b
}
if a > c {
a = c
}
return a
}
Performance of this solution is:
Runtime: 4 ms
Memory Usage: 5.7 MB