comefrom: <gouthampradhan>array_MissingNumber_1.java
code: public int missingNumber(int[] nums) {
      int sum = 0;
      int n = nums.length;
      for (int num : nums) {
        sum += num;
      }
      int arrSum = (((n + 1)) * n) / 2;
      if (arrSum == sum) return 0;
      else return arrSum - sum;
    }
masked: public int sample_funcname ( int [ ] var_0 ) {
    int var_2 = 0 ;
    int var_4 = var_0 . length ;
    for ( int var_5 : var_0 ) {
      var_2 += var_5 ;
    }
    int var_8 = ( ( ( var_4 + 1 ) ) * var_4 ) / 2 ;
    if ( var_8 == var_2 ) return 0 ;
    else return var_8 - var_2 ;
  }
  