HDU 1896 Stones

#include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>
using namespace std;
#define maxn 100010
struct Node
{
    int x,y,id;
    friend bool operator < (Node a,Node b)
    {
        if(a.x != b.x) return a.x > b.x;
        else if(a.y != b.y) return a.y > b.y;
        else return a.id < b.id;
    }
} node[maxn];
priority_queue<Node>que;
int main()
{
    int t,n;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d",&n);
        for(int i = 0; i < n; i++)
        {
            scanf("%d%d",&node[i].x,&node[i].y);
            node[i].id = i+1;
            que.push(node[i]);
        }
        int tot = 0,maxt = -9999;
        while(!que.empty())
        {
            tot++;
            Node tmp = que.top();
            que.pop();
            if(tot & 1 == 1)
            {
                Node next = tmp;
                next.x = tmp.x + tmp.y;
                if(next.x > maxt) maxt = next.x;
                que.push(next);
            }
        }
        printf("%d\n",maxt);
    }
    return 0;
}