Implemented a sudoku solver

Java/sudoku-solver

@@ -0,0 +1,37 @@
+private char[][] b;
+private boolean[][] row = new boolean[9][9];
+private boolean[][] col = new boolean[9][9];
+private boolean[][] block = new boolean[9][9];
+public void solveSudoku(char[][] board) {
+    b = board;
+    int num, k;
+    for (int i=0; i<9; i++) {
+        for (int j=0; j<9; j++) {
+            if(board[i][j]!='.') {
+                num = board[i][j]-'1'; 
+                k = i/3*3 + j/3;
+                row[i][num] = col[j][num] = block[k][num] = true;
+            }
+        }
+    }
+    Helper(0);
+}
+public boolean Helper(int ind){
+    if(ind==81) return true; 
+    int i=ind/9, j=ind%9, num, k;
+    if(b[i][j]!='.') return Helper(ind+1);
+    else{
+        for(char f='1'; f<='9'; f++){
+            num = f-'1'; 
+            k= i/3*3 + j/3;
+            if(!row[i][num] && !col[j][num] && !block[k][num]){
+                b[i][j]= f;
+                row[i][num] = col[j][num] = block[k][num] = true;
+                if(Helper(ind+1)) return true;                
+                b[i][j]='.';
+                row[i][num] = col[j][num] = block[k][num] = false;
+            }
+        }
+        return false;
+    }
+}