Stones（优先队列）

最新推荐文章于 2022-03-06 21:24:46 发布

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本文介绍了一个基于石头位置和投掷距离的游戏算法问题。通过使用优先队列数据结构，实现了一个可以计算出玩家行走过程中最远石头位置的算法。文章包含了完整的代码示例，并解释了优先队列的工作原理。

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Stones

Time Limit: 5000/3000 MS (Java/Others) Memory Limit: 65535/32768 K (Java/Others)
Total Submission(s): 1272 Accepted Submission(s): 784

Problem Description

Because of the wrong status of the bicycle, Sempr begin to walk east to west every morning and walk back every evening. Walking may cause a little tired, so Sempr always play some games this time.
There are many stones on the road, when he meet a stone, he will throw it ahead as far as possible if it is the odd stone he meet, or leave it where it was if it is the even stone. Now give you some informations about the stones on the road, you are to tell me the distance from the start point to the farthest stone after Sempr walk by. Please pay attention that if two or more stones stay at the same position, you will meet the larger one(the one with the smallest Di, as described in the Input) first.

Input

In the first line, there is an Integer T(1<=T<=10), which means the test cases in the input file. Then followed by T test cases.
For each test case, I will give you an Integer N(0<N<=100,000) in the first line, which means the number of stones on the road. Then followed by N lines and there are two integers Pi(0<=Pi<=100,000) and Di(0<=Di<=1,000) in the line, which means the position of the i-th stone and how far Sempr can throw it.

Output

Just output one line for one test case, as described in the Description.

Sample Input

Sample Output

  
   11
12

Author

Sempr|CrazyBird|hust07p43

Source

HDU 2008-4 Programming Contest

是奇数就扔，是偶数就忽略！记住就是在同一点的石头不算一个

有几个算几个！优先队列！

关于优先队列的详解看这里！优先队列

#include<cstdio>
#include<iostream>
#include<queue>
#include<vector>
using namespace std;
struct node
{
    int pos;
    int dis;
};
struct cmp{
    bool operator () (node a,node b){
        if(a.pos!=b.pos)
            return a.pos>b.pos;
        else
            return a.dis>b.dis;
    }
};
int main()
{
    priority_queue<node,vector<node>,cmp>s;
    int t,n1,num,result;
    cin>>t;
    while(t--)
    {
        node n;
        cin>>n1;
        while(n1--)
        {
            cin>>n.pos>>n.dis;
            s.push(n);
        }
        num=1;
        while(!s.empty())
        {
            n=s.top();
            s.pop();
            if(num&1)
            {
                n.pos+=n.dis;
                s.push(n);
            }
            num++;
            result=n.pos;
        }
        cout<<result<<endl;
    }
}

struct cmp{
bool operator () (node a,node b){
if(a.pos!=b.pos)
return a.pos>b.pos;
else
return a.dis>b.dis;
}
};

这里要说一下，为什么这个明明排序是头大尾小，为什么输出是

头小尾大呢？

看这个吧，可能与这个机制有关记住就行了！