[NOI.AC]COUNT(数学)

解析:

也可以将所有的可能都计算出来,后进行减法运算。

代码:

#include<bits/stdc++.h>
using namespace std;
#define ll long long 
#define rint register int

inline int read(){
    int x=0,f=0;char ch=getchar();
    while(!isdigit(ch)) f=(ch==45),ch=getchar();
    while( isdigit(ch)) x=(x<<1)+(x<<3)+(ch^48),ch=getchar();
    return f?(~x+1):x;
}

const ll md=1e9+7;
#define man 100050

int n;
long long fac[man],inv[man];
int x,y,xx,yy,a[man],v[man];

inline long long bpow(long long a,int b){
    long long ans=1;a%=md;
    while(b){
        if(b&1) ans=ans*a%md;
        a=a*a%md;
        b>>=1;
    }
    return ans;
}

inline ll C(ll nn,ll mm){
    ll ret=fac[nn]*inv[mm]%md*inv[nn-mm]%md;
    return ret%md;
}

int main(){
    n=read();
    memset(v,0,sizeof(v));
    for(rint i=1;i<=n+1;i++){
        scanf("%d",&a[i]);
        if(v[a[i]]!=0) xx=v[a[i]],yy=i;
        if(v[a[i]]==0) v[a[i]]=i;
        
    }
    
    x=xx-1;y=n+1-yy;
    fac[0]=inv[0]=1;
    for(rint i=1;i<=n+1;i++)
        fac[i]=fac[i-1]*i%md,inv[i]=bpow(fac[i],md-2);
    
    printf("%d
",n);
    for(rint i=2;i<=n;i++){
        ll ans=0;
        if(x+y>=i-1) ans=(C(n+1,i)-C(x+y,i-1)+md)%md;
        else ans=C(n+1,i)%md;
        while(ans<0) ans=(ans+md)%md;
        printf("%lld
",ans);
    }
    printf("1
");
    return 0;
}
原文地址:https://www.cnblogs.com/Slager-Z/p/9896849.html