hdu 5720(贪心)

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

typedef long long LL;
typedef pair<LL,LL> Pi;
LL x[100005];
Pi pr[100005];

int main()
{
	int t;
	scanf("%d",&t);
	while(t--)
	{
		int n;
		LL L,R;
		scanf("%d%lld%lld",&n,&L,&R);
		for(int i = 0; i < n; ++i) scanf("%lld",&x[i]);
		sort(x,x+n);
		for(int i = 0; i < n-1; ++i)
		{
			pr[i].first = x[i+1]-x[i];
			pr[i].second = x[i+1]+x[i];
		}
		sort(pr,pr+n-1);
		LL ans = 0;
		LL mx = L;
		for(int i = 0; i < n-1 && pr[i].first <= R; ++i)
		{
			if(pr[i].first >= mx) ans += (pr[i].first-mx+1);
			mx = max(mx,pr[i].second);
		}
		ans += max(0LL,R+1-mx);
		printf("%lld\n",ans);
	}
	return 0;
}