签到题看错模数。。。 1e8+7 什么鬼

#include <stdio.h>
#include <iostream>

typedef long long ll;
using namespace std;
const ll Mod = 1e8+7;

ll n, m, i, j, k;

ll qp(ll a, ll b) {
    ll res = 1;
    while(b) {
        if(b & 1) res = res*a % Mod;
        a = a*a % Mod;
        b >>= 1;
    }
    return res;
}
ll inv(ll x) { return qp(x, Mod-2); }
ll C(ll n, ll m) {
    ll ans = 1, div = 1;
    for(i = n-m+1; i <= n; ++i) ans = ans*i % Mod;
    for(i = 2; i <= m; ++i) div = div*i % Mod;
    return ans*inv(div) % Mod;
}
int main() {
    cin >> n >> m;
    m = min(m, n-m);
    cout << C(n, m);
    return 0;
}

「10年OI一场空，看错模数见祖宗」

然后就是求C(n,m)，没别的了

#include<iostream>
using namespace std;
#define ll long long
const ll M = 1e8 + 7;
ll qpow(ll a, ll b){
    ll ans = 1, base = a;
    while (b){
        if (b&1) ans = ans * base % M;
        base = base * base % M;
        b >>= 1;
    }
    return ans;
}
int main(){
    ll n, m, c=1;
    cin >> n >> m;
    for (int i = 1;i <= m;++i){
        c = c * (n+1-i) % M;
        c = c * qpow(i, M-2) % M;
    }
    cout << c;
}