NC20154 [JSOI2007]建筑抢修

题目地址：

https://ac.nowcoder.com/acm/problem/20154

基本思路：

参考代码：

#pragma GCC optimize(2)
#pragma GCC optimize(3)
#include <bits/stdc++.h>
using namespace std;
#define IO std::ios::sync_with_stdio(false)
#define int long long
#define rep(i, l, r) for (int i = l; i <= r; i++)
#define per(i, l, r) for (int i = l; i >= r; i--)
#define mset(s, _) memset(s, _, sizeof(s))
#define pb push_back
#define pii pair <int, int>
#define mp(a, b) make_pair(a, b)
#define INF (int)1e18

inline int read() {
  int x = 0, neg = 1; char op = getchar();
  while (!isdigit(op)) { if (op == '-') neg = -1; op = getchar(); }
  while (isdigit(op)) { x = 10 * x + op - '0'; op = getchar(); }
  return neg * x;
}
inline void print(int x) {
  if (x < 0) { putchar('-'); x = -x; }
  if (x >= 10) print(x / 10);
  putchar(x % 10 + '0');
}


int n,x,y;
struct Node{
    int t1,t2;
    bool operator < (const Node &no) const {
      return t2 < no.t2;//按照截止时间排序;
    }
};
vector<Node> v;
signed main() {
  IO;
  cin >> n;
  priority_queue<int> que;
  rep(i,1,n){
    cin >> x >> y;
    v.push_back({x,y});
  }
  sort(v.begin(),v.end());
  int sum = 0,ans = 0;
  for(auto it : v){
    if(sum + it.t1 <= it.t2){//可以填加的情况先添加;
      sum += it.t1; que.push(it.t1);
      ans++;
    }else if(!que.empty() && que.top() > it.t1){//不能添加的情况替换最大;
        sum -= que.top(); que.pop();
        sum += it.t1 ; que.push(it.t1);
    }
  }
  cout << ans << '\n';
  return 0;
}