https://leetcode.com/problems/edit-distance

edit-distance.js

/**
 * @param {string} word1
 * @param {string} word2
 * @return {number}
 */
let minDistance = function(word1, word2) {
   let a = word1.split("")
   let b = word2.split("")
   let n = a.length
   let m = b.length
   const INF = 3214567;
   let dp = Array.from(Array(n+1), () => new Array(m+1))
      
   for (let i = 0; i <= n; i++) {
       for (let j = 0; j <= m; j++) {
           if (i + j === 0) {
               dp[i][j] = 0;
               continue;
           }
           dp[i][j] = INF
           if (i > 0 && j > 0 && a[i - 1] == b[j - 1]) {
               dp[i][j] = Math.min(dp[i][j], dp[i - 1][j - 1])
           }
           if (i > 0 && j > 0 && a[i - 1] != b[j - 1]) {
               dp[i][j] = Math.min(dp[i][j], dp[i - 1][j - 1] + 1)
           }
           if (i > 0) {
               dp[i][j] = Math.min(dp[i][j], dp[i - 1][j] + 1)
           }
           if (j > 0) {
               dp[i][j] = Math.min(dp[i][j], dp[i][j - 1] + 1)
           }
       }
   }   
   return dp[n][m]
};