Submission #5946129

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i,n) for(int i=0;i<n;i++)
#define all(a) a.begin(),a.end()
#define P pair<int,int>
#define F first
#define S second
#define mod 1000000007
#define INF 9000000000000000000
signed main(void){
    string s;cin>>s;
    vector<int>C(26,0);
    rep(i,s.size()){
        C[s[i]-'a']++;
    }
    int sum=0;
    int n=s.size();
    rep(i,26)sum+=C[i]*C[i];
    cout<<(n*n-sum)/2+1<<endl;
}

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