hdu 6333 多校第4场B

代码如下

#include
#include
#include
#include
#include
using namespace std;
typedef long long ll;
const int maxn=100005;
ll f[maxn]={1,1},inv[maxn]={1,1},finv[maxn]={1,1},ans[maxn];
int pos[maxn],sz,t;
const ll M=1e9+7;
struct Node
{
    int m,n,id;
}q[maxn];
void init()
{
    for(int i=2;i<=maxn;i++) {
        f[i]=f[i-1]*i%M;
        inv[i]=(M-M/i)*inv[M%i]%M;
        finv[i]=finv[i-1]*inv[i]%M;
    }
}
ll C(int n,int m)
{
    if(m>n) {
        return 0;
    }
    return f[n]*finv[m]%M*finv[n-m]%M;
}
bool cmp(Node a,Node b)
{
    if(pos[a.m]==pos[b.m]) {
        return a.nq[i].n) {sum=(sum+C(--n,m))%M*inv[2]%M; }
        while(mq[i].m) {sum=(sum-C(n,m--)+M)%M; }
        ans[q[i].id]=sum;
    }
    for(int i=1;i<=t;i++) {
        printf("%lld\n",ans[i]);
    }
}