Osajono

#include <iostream>

using std::cout;
using std::cin;
using std::endl;

const size_t SIZE = 'Z'-'A';
unsigned table[SIZE] = {};

int main () {
  long result(0);
  char c;

  while (cin >> c) {
    ++table[c-'A'];
  }

  for (size_t i = 0; i < SIZE; ++i) {
    long value = table[i];
    result += value * (value + 1) / 2;
  }

  cout << result << endl;

  return 0;
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: WRONG ANSWER

Test 3

Group: 1

Verdict: WRONG ANSWER

Test 4

Group: 1

Verdict: WRONG ANSWER

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: WRONG ANSWER

Test 8

Group: 2

Verdict: WRONG ANSWER

Test 9

Group: 2

Verdict: WRONG ANSWER

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: WRONG ANSWER

Test 13

Group: 3

Verdict: WRONG ANSWER

Test 14

Group: 3

Verdict: WRONG ANSWER

Test 15

Group: 3

Verdict: ACCEPTED