Submission #1113075

---

Source Code Expand

#include<cstdio>
#include<cstring>
#include<vector>
#include<queue>
#include<algorithm>
#include<cmath>
#include<climits>
#include<string>
#include<set>
#include<map>
#include<iostream>
using namespace std;
#define rep(i,n) for(int i = 0;i<((int)(n));i++)
#define reg(i,a,b) for(int i = ((int)(a));i<=((int)(b));i++)
#define irep(i,n) for(int i = ((int)(n)-1);i>=0;i--)
#define ireg(i,a,b) for(int i = ((int)(b)-1);i>=((int)(a));i--)
typedef long long int lli;
typedef pair<int, int> mp;
#define fir first
#define sec second
#define IINF INT_MAX
#define LINF LLONG_MAX
#define eprintf(...) fprintf(stderr,__VA_ARGS__)
#define pque(type) priority_queue<type,vector<type>,greater<type> >
#define memst(a,b) memset(a,b,sizeof(a))

#define MOD 1000000007

int main(void){
	int n; scanf("%d", &n);
	int a[n];
	rep(i, n) a[i] = 0;
	rep(i, n){
		int t; scanf("%d", &t);
		a[t]++;
	}
	if(n%2 == 1 && a[0] != 1){
		cout << 0 << endl;
		return 0;
	}
	for(int j = (n%2)+1 ; j <= n-1 ; j += 2) if(a[j] != 2){
		cout << 0 << endl;
		return 0;
	}
	
	lli ans = 1;
	rep(i, n/2){
		ans = (ans*2) % MOD;
	}

	cout << ans << endl;
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:30:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  int n; scanf("%d", &n);
                        ^
./Main.cpp:34:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   int t; scanf("%d", &t);
                         ^

Judge Result