Submission #1364672

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Source Code Expand

#include <algorithm>  
#include <iostream>  
#include <sstream>  
#include <string>  
#include <cstring>
#include <vector>  
#include <queue>  
#include <set>  
#include <map>  
#include <cstdio>  
#include <cstdlib>  
#include <cctype>  
#include <cmath>  
#include <list>  
#include <cassert>
#include <ctime>
#include <climits>
using namespace std;  

#define PB push_back  
#define MP make_pair  
#define SZ(v) ((int)(v).size())  
#define FOR(i,a,b) for(int i=(a);i<(b);++i)  
#define REP(i,n) FOR(i,0,n)  
#define FORE(i,a,b) for(int i=(a);i<=(b);++i)  
#define REPE(i,n) FORE(i,0,n)  
#define FORSZ(i,a,v) FOR(i,a,SZ(v))  
#define REPSZ(i,v) REP(i,SZ(v))  
typedef long long ll;
typedef unsigned long long ull;
ll gcd(ll a,ll b) { return b==0?a:gcd(b,a%b); }

const int MAXN=15;
const int MOD=1000000007;

int n,m;
int adj[MAXN];
int mem[1<<MAXN];
int bcnt[1<<MAXN];

int go(int mask) {
	if(mask==0) return 1;
	if(mem[mask]!=-1) return mem[mask];
	//printf("go(%d)\n",mask);
	int ret=0;
	int donemask=(1<<n)-1-mask;
	for(int nxtmask=(donemask+1)&mask;nxtmask!=0;nxtmask=(nxtmask+donemask+1)&mask) {
		bool a=(nxtmask&1)!=0,b=(nxtmask&2)!=0; if(a!=b) continue;
		int remmask=mask-nxtmask;
		int ways=1;
		REP(i,n) if(remmask&(1<<i)) {
			int cnt=bcnt[adj[i]&nxtmask];
			int curways=(1<<cnt)-1;
			ways=(ll)ways*curways%MOD;
		}
		REP(i,n) if(nxtmask&(1<<i)) {
			int cnt=bcnt[adj[i]&remmask];
			int curways=(1<<cnt);
			ways=(ll)ways*curways%MOD;
		}
		int res=go(remmask);
		ret=(ret+(ll)ways*res)%MOD;
	}
	return mem[mask]=ret;
}

void run() {
	scanf("%d%d",&n,&m); REP(i,n) adj[i]=0;
	REP(i,m) { int a,b; scanf("%d%d",&a,&b); --a,--b; adj[a]|=1<<b; }
	memset(mem,-1,sizeof(mem));
	bcnt[0]=0; FOR(i,1,1<<n) bcnt[i]=1+bcnt[i-(i&-i)];
	int tot=1; REP(i,m) tot=(ll)2*tot%MOD;
	int lose=go((1<<n)-1);
	int ret=(tot-lose+MOD)%MOD;
	printf("%d\n",ret);
}

int main() {
	run();
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘void run()’:
./Main.cpp:68:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m); REP(i,n) adj[i]=0;
                     ^
./Main.cpp:69:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  REP(i,m) { int a,b; scanf("%d%d",&a,&b); --a,--b; adj[a]|=1<<b; }
                                         ^

Judge Result