comefrom: <awangdev>567. Permutation in String_1.java
code: private Integer[] countFreq(String s) {
  
          Integer[] freq = new Integer[256];
          for (char c : s.toCharArray()) freq[c] = freq[c] == null ? 1 : freq[c] + 1;
          return freq;
      }
masked: private Integer [ ] var_0 ( String var_2 ) {
    Integer [ ] var_5 = new Integer [ 256 ] ;
    for ( char var_7 : var_2 . toCharArray ( ) ) var_5 [ var_7 ] = var_5 [ var_7 ] == null ? 1 : var_5 [ var_7 ] + 1 ;
    return var_5 ;
  }
  