Submission #70031

#	Time	Username	Problem	Language	Result	Execution time	Memory
70031		yogahmad	Asceticism (JOI18_asceticism)	C++14	100 / 100	29 ms	2328 KiB

asceticism

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define fbo find_by_order
#define ook order_of_key
#define f first
#define s second
#define pb push_back
#define reset(a,b) memset(a,b,sizeof a);
#define MOD 1000000007
#define MID (l+r)/2
#define ALL(x) x.begin(),x.end()
#define debug(x) cout<<#x<<" = "<<(x)<<endl
#define mx 100003
#define pc(x) putchar_unlocked(x);
typedef tree<long long, null_type, less<long long>, rb_tree_tag, tree_order_statistics_node_update> pbds;

long long fak[mx],inv[mx],n,k;

long long C(int n,int k){
	long long ret=fak[n]*inv[k]%MOD;
	ret=ret*inv[n-k]%MOD;
	return ret;
}

long long pow_(long long a,int b){
	if(b==0)return 1;
	long long sem=pow_(a,b/2);
	sem=(sem*sem)%MOD;
	if(b&1)sem=(sem*a)%MOD;
	return sem;
}

int main(){
	fak[1]=inv[1]=inv[0]=inv[1]=1;
	for(int i=2;i<=1e5+5;i++){
		fak[i]=fak[i-1]*i%MOD;
		inv[i]=(MOD-1LL*(MOD/i)*inv[MOD%i]%MOD)%MOD;
	}
	for(int i=1;i<=1e5+5;i++){
		inv[i]=inv[i]*inv[i-1]%MOD;
	}
	long long m;
	cin>>n>>m;
	long long jaw=0;
	m--;
	for(int k=0;k<=m;k++){
		long long sem;
		sem=C(n+1,k)*pow_(m+1-k,n)%MOD;
		if(k&1){
			sem=(MOD-sem)%MOD;
		}
		jaw=(jaw+sem)%MOD;
	}
	cout<<jaw<<endl;
}

Compilation message (stderr)

asceticism.cpp: In function 'int main()':
asceticism.cpp:37:15: warning: operation on 'inv[1]' may be undefined [-Wsequence-point]
  fak[1]=inv[1]=inv[0]=inv[1]=1;
         ~~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 20 / 20
• Subtask 3: 25 / 25
• Subtask 4: 51 / 51