CCF 1-2 question answering record (1)

It's called checkpoint query

//#include <bits/stdc++.h> // Submitted to the CCF Need to add universal header file 
#include <iostream>
#include <math.h>
using namespace std;

struct PointD{
	int PointN;
	double D;
	struct PointD* next;
};
	
int main(){
	int x,y,n,xi,yi;
	double distance;
	struct PointD* p=new struct PointD;
	struct PointD* head=p;
	struct PointD* preP;
	scanf("%d %d %d",&n,&x,&y);
	for(int i=0;i<n;++i){
		scanf("%d %d",&xi,&yi);
		distance=(sqrt(pow(xi-x,2)+pow(yi-y,2)));
		p->PointN=i+1;
		p->D=distance;
		preP=p;
		p=p->next=new struct PointD;
	}
	preP->next=NULL;
	
	//sorting
	struct PointD* pre=new struct PointD;
	pre->next=head;
	for(int i=0;i<3;++i){
		int minN=pre->next->PointN;
		double minD=pre->next->D;
		struct PointD* preMin=pre;
		
		for(struct PointD* temp=pre;temp->next->next;temp=temp->next){
			if(temp->next->D < minD){
				minN=temp->next->PointN;
				minD=temp->next->D;
				preMin=temp;
			}
			else if(temp->next->D == minD){
				if(temp->next->PointN < minN){
					minN=temp->next->PointN;
					minD=temp->next->D;
					preMin=temp;
				}
			}
		}
		struct PointD* f=preMin->next;
		preMin->next=preMin->next->next;
		free(f);
		cout<<minN<<endl;
	}
return 0;
}

Screening for people at risk

#include <bits/stdc++.h>
using namespace std;

//boolean: check the point stands in the square or not
bool examine(int xl,int yd,int xr,int yu,int xi,int yi){
	if(xi>=xl && yi>=yd && xi<=xr && yi<=yu){
		return 1;
	}
	else{
		return 0;
	}
}

int main(){
	int n,k,t,xl,yd,xr,yu,x,xi,yi;
	int whether;int stay=0;int passBy=0;
	scanf("%d %d %d %d %d %d %d",&n,&k,&t,&xl,&yd,&xr,&yu);
	for(int i=0;i<n;i++){
		vector<int> point;
		int sum=0;int continuous=0;int isStay=0;
		for(int j=0;j<(2*t);j++){
			cin>>x;
			point.push_back(x);
		}
		for(int i=0;i<(2*t-1);i=i+2){
			xi=point[i];
			yi=point[i+1];
			//cout<<"xi: "<<xi<<" yi: "<<yi<<endl;
			whether=examine(xl,yd,xr,yu,xi,yi);
			//cout<<"whether: "<<whether<<endl;
			sum += whether;
			//cout<<"sum: "<<sum<<endl;
			if(whether){
				continuous++;
				if(continuous>=k){
					isStay=1;
				}
			}
			else{
				continuous=0;
				}
		}
		if(isStay){
			stay++;
			//cout<<"stay: "<<stay<<endl;
		}
		//cout<<"cintinuous: "<<continuous<<endl;
		//cout<<"isStay: "<<isStay<<endl;
		if(sum>=1){
			passBy++;
			//cout<<"passBy: "<<passBy<<endl;
		}
	}
	cout<<passBy<<endl;
	cout<<stay;
	return 0;
}

Safety index of final forecast

#include <iostream>
#include <math.h>
using namespace std;

int main(){
	int n,wi,scorei,sum=0;
	cin>>n;
	if(n<2 || n>pow(10,5)){
		return 0;
	}
	for(int i=0;i<n;i++){
		scanf("%d %d",&wi,&scorei);
		sum+=wi*scorei;
	}
	int y=max(0,sum);
	cout<<y;
	return 0;
}

The best threshold of final forecast

#include <iostream>
#include <math.h>
#include <vector>
#include <algorithm>
#include <set>
using namespace std;

int main(){
	int m; // row
	cin>>m;
	if(m<2 || m>pow(10,5)){
		return 0;
	}
	vector<int> y;
	vector<int> result;
	int yi,resulti;
	for(int i=0;i<m;++i){
		scanf("%d %d",&yi,&resulti);
		y.push_back(yi);
		result.push_back(resulti);
	}
	vector<int> B(m);
	set<int> temp(y.begin(),y.end());
	B.assign(temp.begin(),temp.end());
	
	vector<int> sum(B.size(),0);
	for(int i=0;i<B.size();i++){
		for(int j=0;j<m;j++){
			sum[i] += (y[j]>=B[i] == result[j]);
		}
		//cout<<sum[i]<<endl; //debug
	}
	vector<int> sum_sort=sum;
	sort(sum_sort.begin(),sum_sort.end());
	int sum_max=sum_sort.back();
	vector<int> num;
	for(int i=0;i<B.size();++i){
		if(sum[i]==sum_max){
			num.push_back(i);
		}
	}
	/*for(int i=0;i<num.size();i++){
		cout<<num[i]<<endl;
	}*/
	sort(num.begin(),num.end());
	int B_best=num.back();
	cout<<B[B_best];
	return 0;
}