Osajono

#include <iostream>
#include <algorithm>
#include <queue>
#include <stack>
#include <string>

using namespace std;

int main()
{
    string s;
    cin>>s;

    long long v[27];
    for (int i = 0; i < 27; i++) v[i] = 0;

    for (char c : s) {
        v[c - 'A']++;
    }

    long long ans = 0;

    for (long long i : v) {
        ans += (i + 1) * i / 2;
    }

    cout<<ans<<endl;

    return 0;
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED