POJ 2437 贪心+priority_queue

题意：

思路：
贪心 能不覆盖的就不盖
写得很乱 左闭右开的 temp

//By SiriusRen#include <queue>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;int n,l,temp,ans;struct Node{int from,to;}node[10050];priority_queue<Node>pq;bool operator < (Node a,Node b){    return a.from>b.from;} int main(){    scanf("%d%d",&n,&l);    for(int i=1;i<=n;i++){        scanf("%d%d",&node[i].from,&node[i].to),node[i].to--;        pq.push(node[i]);    }    while(!pq.empty()){        Node t=pq.top();pq.pop();        if(temp<=t.from){            int rec=(t.to-t.from+1)/l;            ans+=rec;            temp=t.from+l*rec;            if(temp<=t.to)ans++,temp+=l;        }        else if(temp>t.to)        {            continue;        }        else{            int rec=(t.to-temp+1)/l;            ans+=rec;temp+=l*rec;            if(temp<=t.to)ans++,temp+=l;        }    }    printf("%d\n",ans);}