Problem:
Score : 100 points

Problem Statement

On the Planet AtCoder, there are four types of bases: A, C, G and T. A bonds with T, and C bonds with G.

You are given a letter b as input, which is A, C, G or T. Write a program that prints the letter representing the base that bonds with the base b.

Constraints

b is one of the letters A, C, G and T.

Input

Input is given from Standard Input in the following format:

b

Output

Print the letter representing the base that bonds with the base b.

Sample Input 1

A

Sample Output 1

T

Sample Input 2

G

Sample Output 2

C

Solution in C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>

int main(void)
{
  int len, q;
  scanf("%d%d", &len, &q);

  char str[len + 1];
  scanf("%s", str);

  int i, j, k;
  int table[len];

  table[0] = 0;
  for(i = 1; i < len; i++)
    {
      if(str[i - 1] == 'A' && str[i] == 'C') {
        table[i] = table[i - 1] + 1;
        i++;
      }
      else {
        table[i] = table[i - 1];
      }
    }

  int answers[len];
  for(i = 0; i < q; i++) {
    scanf("%d%d", &j, &k);
    answers[i] = table[k - 1] - table[j - 1];
  }
  for(i = 0; i < q; i++) {
    printf("%d\n", answers[i]);
  }
  return 0;
}