#include <bits/stdc++.h>
using namespace std;

int main() {
    freopen("swap.in", "r", stdin);
    freopen("swap.out", "w", stdout);
    string s;
    map<char, int> mp;
    cin >> s;
    long long cnt = 0;
    for (int i = 0; i < s.size(); i ++) {
    	cnt += i - mp[s[i]];
    	mp[s[i]] ++;
    }
    bool ch = 0;
    for (int i = 0; i < s.size(); i ++)
    	for (int j = i + 1; j < s.size(); j ++)
    		if (s[i] == s[j]) {
    			ch = 1;
    			break;
    		}
    cout << cnt + ch;
    fclose(stdin);
    fclose(stdout);
    
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
int main(){
    double x,n;
    cin>>x>>n;
    double s;
    if(450-10*abs(45-x)==0) s=0; 
    else s=n/(450-10*abs(45-x));
    printf("%.2lf",s);
    return 0;
}

中国人民解放军机关枪的射击距离（简单数学）

#include<bits/stdc++

#include<bits/stdc++.h>
using namespace std;
int main(){
double x,n;
cin>>x>>n;
double s;
if(450-10abs(45-x)==0) s=0;
el

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