CF306 b

Preparing Olympiad.cc

#include <cstdio>
#include <cmath>
#include <cstring>
#include <ctime>
#include <iostream>
#include <algorithm>
#include <set>
#include <vector>
#include <sstream>
#include <typeinfo>
#include <fstream>
#include <unordered_map>
#include <bitset>
using namespace std;
typedef vector<int> vi;

int main(){
	int n,l,r,x;
	cin>>n>>l>>r>>x;
	vi v(n, 0);
	for(int i=0;i<n;++i)  cin>>v[i];

	int cnt=0;
	//search all 2^n
	for(int i=0;i<(1<<n);++i){
		int total=0;
		int sm = 1000000, lg = 0;
		for(int p=0;p<n;++p) if((1<<p)&i){
			total += v[p];
			sm = min(sm, v[p]);
			lg = max(lg, v[p]);
		}
		//check constraints
		if(lg-sm>=x && total<=r && total>=l) cnt++;
	}
	cout<<cnt<<endl;
	return 0;
}