poj 3190 Stall Reservations1

堆 + 贪心 

难得的好题，自己确实没想到，看了下别人的想法。.

http://www.acjoke.com/?p=164   这个链接的证明比较给力

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<vector>
#include<queue>
#include<stack>
#include<algorithm>
using namespace std;
const int maxn = 50050;
struct Line
{
    int l,r,index;
    Line(const int& l = 0,const int& r = 0,const int&index = 0):l(l),r(r),index(index){}
    Line(const Line& rsh)
    {
        l = rsh.l;
        r = rsh.r;
        index = rsh.index;
    }
    bool operator < (const Line& rsh) const
    {
        return l < rsh.l;
    }
};

struct Heap
{
    int id;
    int fin;
    Heap(const int& id = 0 ,const int& fin = 0):id(id),fin(fin){}
    Heap(const Heap& rsh)
    {
        id = rsh.id;
        fin = rsh.fin;
    }
    bool operator < (const Heap& rsh) const
    {
        return fin > rsh.fin;
    }
};

int result[maxn];

vector<Line> lines;
priority_queue<Heap> heaps;

void put_cow( int i,bool flag)
{
    Heap heap;
    if(flag)
    {
        heap.id = heaps.size() + 1;
    }
    else
    {
        heap.id = heaps.top().id;
        heaps.pop();
    }
    heap.fin = lines[i].r;
    result[lines[i].index] = heap.id;
    heaps.push(heap);
}

int main()
{
    #ifdef LOCAL
        freopen("in.txt","r",stdin);
    #endif // LOCAL
    int n;
    scanf("%d",&n);
    int l,r;
    for(int i = 0 ; i < n ; i ++)
    {
        scanf("%d %d",&l,&r);
        lines.push_back(Line(l,r,i));
    }

    sort(lines.begin(),lines.end());
    put_cow(0,true);
    for(int i = 1 ; i < n ; i++)
    {
        put_cow(i,lines[i].l <= heaps.top().fin);
    }

    printf("%d\n",heaps.size());
    for(int i = 0 ; i < n ; i++)
    {
        printf("%d\n",result[i]);
    }
    return 0;
}