Wagner Fischer algorithm implementation in java -

i trying implement wagner-fischer algorithm in java using wikipedia reference

wagner-fischer

java code:

public class stringdistance {  public static void main(string[] args) {     int i, j, m, n, temp, tracker;      int[][] d = new int[50][50];      string s = "kitten";     string t = "sitting";      char u[] = s.tochararray();     char v[] = t.tochararray();      m = u.length;     n = v.length;      (i = 0; <= m; i++) {         d[i][0] = i;     }     (j = 0; j <= n; j++) {         d[0][j] = j;     }      (j = 1; j <= m; j++) {         (i = 1; <= n; i++) {             if (u[i - 1] == v[j - 1]) {                 tracker = 0;             } else {                 tracker = 1;             }              temp = math.min((d[i - 1][j] + 1), (d[i][j - 1] + 1));             d[i][j] = math.min(temp, (d[i - 1][j - 1] + tracker));          }     }      system.out.println("the levenstien distance" + d[n][m]); } } 

but above code working strings equal lengths. if want make work unequal strings.please let me know how overcome issue.

i getting index out of bounds error :

exception in thread "main" java.lang.arrayindexoutofboundsexception: 6 @ stringdistance.main(stringdistance.java:32) 

let's rid of of local variables make clearer why happening:

for (j = 1; j <= u.length; j++) {     (i = 1; <= v.length; i++) {         if (u[i - 1] == v[j - 1]) {             tracker = 0;         } else {             tracker = 1;         } 

you're using i - 1 (which guaranteed in range v) index u , j - 1 (which guaranteed in range u) index v.

so suspect expression:

u[i - 1] == v[j - 1] 

should be

u[j - 1] == v[i - 1] 

i'd suggest declaring variables @ point of first use, in minimal scope, , using 0-based indexing rather 1-based. , conditional operator helps too. loop become:

for (int j = 0; j < u.length; j++) {     (int = 0; < v.length; i++) {         int tracker = u[j] == v[i] ? 0 : 1;         int temp = math.min(d[i][j + 1] + 1, d[i + 1][j] + 1);         d[i + 1][j + 1] = math.min(temp, d[i][j] + tracker);     } }