Submission #19786

#	Time	Username	Problem	Language	Result	Execution time	Memory
19786		jihoon	괄호 (kriii4_R)	C++98	0 / 100	144 ms	8896 KiB

R

#include<cstdio>
#define je 1000000007
long long fact[1000001];

long long gop(long long x,long long y){
	x%=je;y%=je;
	x*=y;x%=je;
	return x;
}

long long hap(long long x,long long y){
	x%=je;y%=je;
	x+=y;x%=je;
	return x;
}

long long div(long long x,long long y){
	x%=je;y%=je;
	int left=je-2;
	long long gopp=y,ret=1;
	while(left){
		if(left&1){
			ret=gop(ret,gopp);
		}
		gopp=gop(gopp,gopp);
		left >>= 1;
	}
	ret=gop(ret,x);
	return ret;
}

long long nCr(int n,int k){
    return div(div(fact[n],fact[k]),fact[n-k]);
}

int main(){
    int n,k;
    long long now=1,r,c,ans=0;
    scanf("%d %d",&n,&k);
    fact[0]=1;
    for(int i=1;i<=n;i++){
        fact[i]=gop(fact[i-1],i);
    }
    for(int i=0;i<=n;i++){
        if(i>=n-i) ans=hap(ans,gop(now,nCr(i,n-i)));
        now=gop(now,k);
    }
    printf("%lld",ans);
}

• Subtask 1: 0 / 8
• Subtask 2: 0 / 92