2276: [Poi2011]Temperature 单调队列

维护一个L[i]单调不增的队列，且如果队首的L大于队尾的R就弹出。

#include<iostream>#include<cstdio>#include<cstring>#define ll long long using namespace std;int l[1000005],r[1000005],q[1000005];int n,now,last=1,ans=1;inline int read(){    int a=0,f=1; char c=getchar();    while (c<'0'||c>'9') {if (c=='-') f=-1; c=getchar();}    while (c>='0'&&c<='9') {a=a*10+c-'0'; c=getchar();}    return a*f;}int main(){    n=read();    for (int i=1;i<=n;i++) l[i]=read(),r[i]=read();    int t=1,w=0;     for (int i=1;i<=n;i++)    {        while (t<=w&&l[q[w]]<=l[i]) w--;        q[++w]=i;        now=last;        while (l[q[t]]>r[i]) now=q[t++]+1;        ans=max(ans,i-now+1);        last=now;    }    cout << ans;    return 0;}