comefrom: <awangdev>387. First Unique Character in a String_1.java
code: public int firstUniqChar(String s) {
          int[] freq = new int[256];
          for (char c : s.toCharArray()) freq[c - 'a']++;
          for (int i = 0; i < s.length(); i++) {
              if (freq[s.charAt(i) - 'a'] == 1) return i;
          }
          return -1;
      }
masked: public int sample_funcname ( String var_1 ) {
    int [ ] var_3 = new int [ 256 ] ;
    for ( char var_5 : var_1 . toCharArray ( ) ) var_3 [ var_5 - 'a' ] ++ ;
    for ( int var_8 = 0 ;
    var_8 < var_1 . length ( ) ;
    var_8 ++ ) {
      if ( var_3 [ var_1 . charAt ( var_8 ) - 'a' ] == 1 ) return var_8 ;
    }
    return - 1 ;
  }
  