奶牛编号

#include <bits/stdc++.h>

using namespace std;


int main(int argc, char const *argv[])
{
    int cow_nums;
    cin >> cow_nums;
    int x[cow_nums];
    for (int i = 0; i < cow_nums; ++i) {
        cin >> x[i];
    }

    sort(x, x + cow_nums);

    long long res = 1;

    for (int i = 0; i < cow_nums; ++i) {
        res *= (x[i] - i);
        res %= 1000000007;
    }

    cout << res;
}

#include <iostream>
#include <vector>
 
using namespace std;
 
int main(){
    int num_niu;
    unsigned long long num_name = 1;
    vector<int> niu;
    int temp1;
    cin >> num_niu;
    for(int i = 0; i<num_niu; i++){
        int temp;
        cin >> temp;
        niu.push_back(temp);
    }
    for(int i = 0; i < niu.size(); i++)
        for(int j = i; j < niu.size(); j++){
            if(niu[i] > niu[j]){ temp1 = niu[j]; niu[j] = niu[i];
                               niu[i] = temp1;}
        }
    int flag = 0;
    for (int i = 0; i < niu.size(); i++){
        if (i == 0) num_name *= niu[i];
        else num_name *= (niu[i] - (++flag));
        num_name %= 1000000007;            //最终死在这步上，不能最后取模，会溢出
    }
    cout << num_name;
    return 0;
}