[POI2010]PIL-Pilots

【代码】

#include<bits/stdc++.h>

#define ll long long

using namespace std;

const int N = 3001000;
ll q_mn[N],q_mx[N],head_mx = 1,head_mn = 1, tail_mx = 0, tail_mn = 0, a[N];
ll ans = 0;
int main() {
	ll n, t, pre = 1;
	scanf("%lld%lld", &t, &n);
	for(int i = 1; i <= n; ++i) {
		scanf("%lld",&a[i]);
		while(head_mx <= tail_mx && a[i] > a[q_mx[tail_mx]])--tail_mx;
		while(head_mn <= tail_mn && a[i] < a[q_mn[tail_mn]])--tail_mn;
		q_mx[++tail_mx] = i;
		q_mn[++tail_mn] = i;
		while(a[q_mx[head_mx]] - a[q_mn[head_mn]] > t) {
			if(q_mx[head_mx] > q_mn[head_mn]) {
				pre = q_mn[head_mn] + 1;
				++head_mn;	
			}else {
				pre = q_mx[head_mx] + 1;
				++head_mx;
			}
		}
		ans = max(ans, i - pre + 1);
	}
	printf("%lld\n", ans);
	return 0;
}