luogu 2698 [USACO12MAR]花盆Flowerpot 单调队列

刷水~

Code:

#include<bits/stdc++.h>
using namespace std;
#define setIO(s) freopen(s".in","r",stdin)
#define maxn 300000
#define inf 1000000
deque<int>p,q;
struct Node
{
    int x,y;
}nd[maxn];
bool cmp(Node a, Node b)
{
    return a.x < b.x;
}
int main()
{
    // setIO("input");
    int n,D,ans=inf;
    scanf("%d%d",&n,&D);
    for(int i=1;i<=n;++i)
    {
        scanf("%d%d",&nd[i].x,&nd[i].y);
    }
    sort(nd+1,nd+1+n,cmp);
    for(int i=1;i<=n;++i)
    {
        while(!p.empty()&&nd[i].y>=nd[p.back()].y) p.pop_back();
        while(!q.empty()&&nd[i].y<=nd[q.back()].y) q.pop_back();
        p.push_back(i), q.push_back(i);
        int pre=0;
        while(!p.empty()&&nd[p.front()].y-nd[i].y>=D) { pre=nd[p.front()].x;  p.pop_front(); }
        if(pre) ans=min(ans, nd[i].x - pre);
        pre=0;
        while(!q.empty()&&nd[i].y-nd[q.front()].y>=D) { pre=nd[q.front()].x;  q.pop_front(); }
        if(pre) ans=min(ans, nd[i].x - pre);
    }
    printf("%d\n",ans==inf?-1:ans);
    return 0;
}