DeleteOperationforTwoStrings.java

class Solution {

    // TC : O(n*m)
    // SC : O(n*m)
    public int minDistance(String word1, String word2) {
        int lenLCS = getLenLCS(word1, word2);
        return word1.length() + word2.length() - 2* lenLCS;
    }

    private int getLenLCS(String s1, String s2){
        int[][] dp = new int[s1.length() + 1][s2.length()+1];

        for(int i=1;i<=s1.length();i++){
            for(int j=1;j<=s2.length();j++){
                if(s1.charAt(i-1) == s2.charAt(j-1)){
                    dp[i][j] = 1 + dp[i-1][j-1];
                } else{
                    dp[i][j] = Math.max(dp[i-1][j], dp[i][j-1]);
                }
            }
        }

        return dp[s1.length()][s2.length()];
    }
}