BZOJ 2276: [Poi2011]Temperature|单调队列

#include<set>
#include<map>
#include<ctime>
#include<queue>
#include<cmath>
#include<cstdio>
#include<vector>
#include<cstring>
#include<cstdlib>
#include<iostream>
#include<algorithm>
#define T 1000006
#define MX 1e9
using namespace std;
int L[T],R[T];
int q[T];
int n,ans=0;
int sc()
{
int i=0,f=1; char c=getchar();
while(c>'9'||c<'0'){if(c=='-')f=-1;c=getchar();}
while(c>='0'&&c<='9')i=i*10+c-'0',c=getchar();
return i*f;
}
int main()
{
n=sc();
for(int i=1;i<=n;i++)L[i]=sc(),R[i]=sc();
int l=1,r=0;
for(int i=1;i<=n;i++)
{
while(l<=r&&R[i]<L[q[l]])l++;
if(l<=r)ans=max(ans,i-q[l]+1);
int t=i; while(l<=r&&L[i]>=L[q[r]])t=q[r],r--;
L[t]=L[i],q[++r]=t;
}
cout<<ans;
return 0;
}