codeforces 725D . Contest Balloons(贪心+优先队列)

题目链接：codeforces 725D . Contest Balloons

先按气球数从大到小排序求出初始名次，并把名次排在第一队前面的队放入优先队列，按w-t-1值从小到大优先，然后依次给气球给排名在前面的的队，给完后自己的气球数减少，继续跟之前排在第一队后面的队比较，考虑是否加入队列，每次记录最好的名次。

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<queue>
using namespace std;
typedef long long ll;
const int N = 300001;
struct team{
    ll t, w, wa;
    team(ll t = 0, ll w = 0):t(t),w(w) { wa = w - t + 1; }
    bool operator < (const team &r)const{
        return r.wa < wa;
    }
}a[N];
bool cmp(team x, team y){
    return x.t > y.t;
}
priority_queue<team>q;
int main(){
    int n, i, j;
    ll ans, a1;
    scanf("%d", &n);
    for(i = 0; i < n; ++i)
        scanf("%lld%lld", &a[i].t, &a[i].w);
    sort(a+1, a+n, cmp);
    for(i = 1; i < n; ++i){
        if(a[i].t > a[0].t)
            q.push(team(a[i].t, a[i].w));
        else break;
    }
    a1 = ans = i;//初始名次
    while(!q.empty()){
        team tt = q.top(); q.pop();
        a[0].t -= tt.wa;
        if(a[0].t < 0) break;
        for(j = i; j < n; ++j){
            if(a[j].t > a[0].t){
                q.push(team(a[j].t , a[j].w));}
            else break;
        }
        a1 += j - i - 1;
        i = j;
        ans = min(ans, a1);
    }
    printf("%lld\n", ans);
    return 0;
}