comefrom: <awangdev>221. Maximal Square_2.java
code: public int maximalSquare(char[][] matrix) {
          if (matrix == null || matrix.length == 0 || matrix[0] == null || matrix[0].length == 0) {
              return 0;
          }
          int m = matrix.length;
          int n = matrix[0].length;
          int[][] dp = new int[m][n];
          int maxLen = 0;
          for (int i = 0; i < m; i++) {
              for (int j = 0; j < n; j++) {
                  dp[i][j] = matrix[i][j] == '1' ? 1 : 0;
                  maxLen = Math.max(dp[i][j], maxLen);
              }
          }
  
          for (int i = 1; i < m; i++) {
              for (int j = 1; j < n; j++) {
                  if (matrix[i][j] == '1') {
                      dp[i][j] = Math.min(Math.min(dp[i - 1][j], dp[i][j - 1]), dp[i - 1][j - 1]) + 1;
                      maxLen = Math.max(dp[i][j], maxLen);
                  }
              }
          }
          return maxLen * maxLen;
      }
masked: public int sample_funcname ( char [ ] [ ] var_0 ) {
    if ( var_0 == null || var_0 . length == 0 || var_0 [ 0 ] == null || var_0 [ 0 ] . length == 0 ) {
      return 0 ;
    }
    int var_4 = var_0 . length ;
    int var_5 = var_0 [ 0 ] . length ;
    int [ ] [ ] var_6 = new int [ var_4 ] [ var_5 ] ;
    int var_7 = 0 ;
    for ( int var_8 = 0 ;
    var_8 < var_4 ;
    var_8 ++ ) {
      for ( int var_9 = 0 ;
      var_9 < var_5 ;
      var_9 ++ ) {
        var_6 [ var_8 ] [ var_9 ] = var_0 [ var_8 ] [ var_9 ] == '1' ? 1 : 0 ;
        var_7 = Math . max ( var_6 [ var_8 ] [ var_9 ] , var_7 ) ;
      }
    }
    for ( int var_8 = 1 ;
    var_8 < var_4 ;
    var_8 ++ ) {
      for ( int var_9 = 1 ;
      var_9 < var_5 ;
      var_9 ++ ) {
        if ( var_0 [ var_8 ] [ var_9 ] == '1' ) {
          var_6 [ var_8 ] [ var_9 ] = Math . min ( Math . min ( var_6 [ var_8 - 1 ] [ var_9 ] , var_6 [ var_8 ] [ var_9 - 1 ] ) , var_6 [ var_8 - 1 ] [ var_9 - 1 ] ) + 1 ;
          var_7 = Math . max ( var_6 [ var_8 ] [ var_9 ] , var_7 ) ;
        }
      }
    }
    return var_7 * var_7 ;
  }
  