dfs Preparing Olympiad

#include <bits/stdc++.h>
using namespace std;
const int N=1e5+10;
int num[N],mum[N];
int n,m,q,t,l,r;
int top,ans,cnt;
void dfs(int sum,int d,int x,int minn)///和，差值,当前循环，最小数
{if(sum>=l&&sum<=r&&d>=q) ans++;if(sum>r) return;///if(sum<l) return;当前累加的sum可能小于lfor(int i=x;i<=n;++i)///dfs中需要保留的数就要保留，特别是for循环。{dfs(sum+num[i],num[i]-minn,i+1,minn);}
}
int main()
{while(cin>>n>>l>>r>>q){ans=0;memset(num,0,sizeof(num));for(int i=1; i<=n; ++i) scanf("%d",&num[i]);sort(num+1,num+1+n);for(int i=1; i<=n; ++i){dfs(num[i],0,i+1,num[i]);///为了参照最大和最小,引入最小数}printf("%d\n",ans);}return 0;
}