Codeforces Round #306 (Div. 2), problem: (B) Preparing Olympiad

#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <cmath>
using namespace std;

typedef long long int int64;

int main(){
    int n, l, r, x;
    int cc[20];
    scanf("%d %d %d %d", &n, &l, &r, &x);
    for(int lx = 0;lx < n;lx++) scanf("%d", cc+lx);
    int cnt = 0;
    for(int sts = 0;sts < (1<<n);sts++){
        int pmin = 1000000000, pmax = -1, pcnt = 0, psum = 0;
        for(int lx = 0;lx < n;lx++)
            if(sts&(1<<lx))
                pcnt++, pmax = max(pmax, cc[lx]), pmin = min(pmin, cc[lx]), psum += cc[lx];
        cnt += (pcnt >= 2) and (l <= psum) and (psum <= r) and (x <= pmax-pmin);
    }
    printf("%d\n", cnt);
    return 0;
}