Edit Distance

public class Solution {
public int minDistance(String word1, String word2) {
if(word1==null||word1.length()==0) return word2.length();
if(word2==null||word2.length()==0) return word1.length();
int[][] dp = new int[word1.length()+1][word2.length()+1];
for(int i=1;i<=word1.length();i++){
dp[i][0]=i;
}
for(int j=1;j<=word2.length();j++){
dp[0][j] = j;
}
for(int i=1;i<=word1.length();i++){
char a = word1.charAt(i-1);
for(int j=1;j<=word2.length();j++){
if(a==word2.charAt(j-1)){
dp[i][j]=dp[i-1][j-1];
}else{
dp[i][j]=Math.min(Math.min(dp[i-1][j-1],dp[i][j-1]),dp[i-1][j])+1;
}
}
}
return dp[word1.length()][word2.length()];
}
}