[Blue Bridge Cup] [10th real topic in 2019] priority of takeout shop

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“ Are you full ” The takeout system maintains N Take away shop , Number 1∼N. Every takeaway has a priority , At the beginning (0 moment ) The priority is 0. Each pass 1 Time units , If there's no order at the takeout , The priority will be reduced 1, At least to 0; And if the takeout shop has an order , Then the priority is not decreased but increased , Every order with priority plus 2. If the priority of a takeout store is higher than 5, It will be added to the priority cache by the system ; If the priority is less than or equal to 3, Will be cleared out of the priority cache .
Given T In time M Order information , Please calculate T How many takeout stores are in the priority cache at the moment .
Input format
The first line contains 3 It's an integer N,M,T.
following M Each line contains two integers ts and id, Express ts Time number id 's take out shop received an order .
Output format
Output an integer to represent the answer .
Data range
1≤N,M,T≤10^5,
1≤ts≤T,
1≤id≤N
sample input ：
2 6 6
1 1
5 2
3 1
6 2
2 1
6 2
sample output ：
1
Sample explanation
6 At the moment ,1 The priority of store No. 2 is reduced to 3, Is removed from the priority cache ;2 The priority of store No 6, Add priority cache . So there is 1
stores (2 Number ) In the priority cache .

#include<bits/stdc++.h>
using namespace std;
int n,m,T;
struct Time{
    
	int t;// moment  
	int id;// Takeout number  
}ti[100005];
struct Shop{
    
	int pre;// The last time an order was received  
	int prior;// Priority of the current store  
	bool flag;// Whether the current store is in priority cache ？ yes ：true  no ：false 
}s[100005];
bool cmp(Time x,Time y){
    
	if(x.t!=y.t){
    
		return x.t<y.t;
	}else return x.id<y.id;
}
int cnt;
int main(){
    
	cin>>n>>m>>T;
	for(int i=0;i<m;i++){
    
		cin>>ti[i].t>>ti[i].id;
	} 
	sort(ti,ti+m,cmp);
	for(int i=0;i<m;i++){
    
		if(ti[i].t>=T+1){
    
			break;
		}
		// Because a takeout store may receive multiple orders at a time , So we need to judge 
		if(s[ti[i].id].pre!=ti[i].t) s[ti[i].id].prior-=(ti[i].t-s[ti[i].id].pre-1);
		if(s[ti[i].id].prior<0) s[ti[i].id].prior=0;
		if(s[ti[i].id].prior<=3&&s[ti[i].id].flag){
    
			s[ti[i].id].flag=false;
		}
		s[ti[i].id].prior+=2;
		if(s[ti[i].id].prior>5&&!s[ti[i].id].flag){
    
			s[ti[i].id].flag=true;
		}
		
		s[ti[i].id].pre=ti[i].t;
	}
	for(int i=1;i<=n;i++){
    
		if(s[i].flag){
    
			int temp=s[i].prior-(T-s[i].pre);
			if(temp<=3) s[i].flag=false;
		}
	}
	for(int i=1;i<=n;i++){
    
		cnt+=s[i].flag;
	}
	cout<<cnt<<endl;
	return 0;
}