//Iterative approach

static int ed(String s1, String s2) {

int m = s1.length();

int n = s2.length();

int dp[][] = new int[m+1][n+1];

for (int i = 0; i <= m; i++)

dp[i][0] = i;

for (int i = 0; i <= n; i++)

dp[0][i] = i;

for (int i = 1; i <= m; i++) {

for (int j = 1; j <= n; j++)

if (s1.charAt(i - 1) == s2.charAt(j - 1))

dp[i][j] = dp[i - 1][j - 1];

else

dp[i][j] = 1+Math.min(dp[i - 1][j - 1], Math.min(dp[i][j - 1], dp[i-1][j]));

}

return dp[m][n];

}

//Recursive approach

static int edRec(String s1, String s2, int m , int n){

if(m==0)

return n;

if(n==0)

return m;

if(s1.charAt(m-1)==s2.charAt(n-1))

return edRec(s1, s2, m-1, n-1);

else

return 1+Math.min(edRec(s1, s2, m-1, n-1), (Math.min (edRec(s1, s2, m, n-1), edRec(s1, s2,m-1,n))));

}

public static void main(String[] args) {

String s1="SATURDAY",s2="SUNDAY";

System.out.println(ed(s1, s2));

System.out.println(edRec(s1, s2, s1.length(), s2.length()));

}