Submission #1357590

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Source Code Expand

#include<iostream>
#include<string>
#include<cmath>
#include<queue>
#include<map>
#include<set>
#include<list>
#include<iomanip>
#include<vector>
#include<functional>
#include<algorithm>
#include<cstdio>
#include<unordered_map>
#define int long long
#define rep(i,a,n) for (int (i)=(a);(i)<(n);(i)++)
using namespace std;
typedef long long ll;
typedef long double ld;
int a[33];
bool l[33];
vector<int>r,y;
int n,x;
void solve(int i){
	if(i==floor(n/2.0)){
		int sum=0;
		for(int j=0;j<floor(n/2.0);j++){
			if(l[j])
				sum+=a[j];
		}
		r.push_back(sum);
		return;
	}
	l[i]=false;
	solve(i+1);
	l[i]=true;
	solve(i+1);
}
void solve2(int i){
	if(i==n){
		int sum=0;
		for(int j=floor(n/2.0);j<n;j++){
			if(l[j])
				sum+=a[j];
		}
		y.push_back(sum);
		return;
	}
	l[i]=false;
	solve2(i+1);
	l[i]=true;
	solve2(i+1);
}
signed  main() {
	cin>>n>>x;
	for(int i=0;i<n;i++){
		cin>>a[i];
	}
	sort(a,a+n);
	solve(0);
	solve2(floor(n/2.0));
	int sum=0;
	for(int i=0;i<r.size();i++){
		int k=lower_bound(y.begin(),y.end(),x-r[i])-y.begin();
		if(k==y.size()) continue;
		while(k<y.size()&&y[k]==x-r[i]){
			sum++;
			k++;
		}
	}
	cout<<sum<<endl;
}

Submission Info

Judge Result