二分T三个点求调

#include<bits/stdc++.h>
using namespace std;
int k,n;
int a[3000006];
int q1[3000006],q2[3000006];
int t1,h1,t2,h2;
bool check(int t) {
	memset(q1,0,sizeof(q1));
	memset(q2,0,sizeof(q2));
	t1=h1=t2=h2=1;
	for(int l=1; l<=n; l++) {
		while(h1<=t1&&a[q1[t1]]>a[l])t1--;
		q1[++t1]=l;
		while(h1<=t1&&q1[h1]+t<=l)h1++;
		while(h2<=t2&&a[q2[t2]]<a[l])t2--;
		q2[++t2]=l;
		while(h2<=t2&&q2[h2]+t<=l)h2++;
		if(l>=t) {
//			cout<<t<<" "<<a[q2[h2]]<<" "<<a[q1[h1]]<<"\n";
			if(a[q2[h2]]-a[q1[h1]]<=k)return 1;
		}

	}
	return 0;
}
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0),cout.tie(0);
	cin>>k>>n;
	for(int i=1; i<=n; i++) {
		cin>>a[i];
	}
	int l=1,r=n;
	while(l<r) {
		int mid=l+r+1>>1;
		if(check(mid))l=mid;
		else r=mid-1;
	}
	cout<<l;
}