双指针合并

#include<bits/stdc++.h>
using namespace std;
struct athl{
	long long s,w,id;
}athlete[200009];
athl winner[200009];
athl loser[200009];
long long n,r,q;
bool cmp(athl a,athl b){
	if(a.s!=b.s){
		return a.s>b.s;
	}
	else{
		return a.id<b.id;
	}
}
void merge(){
	long long idx=0;
	for(int i=1;i<=2*n;i+=2){
		idx++;
		if(athlete[i].w>athlete[i+1].w){
			athlete[i].s++;
			winner[idx]=athlete[i];
			loser[idx]=athlete[i+1];
		}
		else{
			athlete[i+1].s++;
			winner[idx]=athlete[i+1];
			loser[idx]=athlete[i];
		}
	}
	long long i=1,j=1;
	long long idx2=0;
	while(i<=idx&&j<=idx){
		if(winner[i].s!=loser[j].s){
			if(winner[i].s>loser[j].s){
				idx2++;
				athlete[idx2]=winner[i];
				i++;
			}
			else{
				idx2++;
				athlete[idx2]=loser[j];
				j++;
			}
		}
		else{
			if(winner[i].id<loser[j].id){
				idx2++;
				athlete[idx2]=winner[i];
				i++;
			}
			else{
				idx2++;
				athlete[idx2]=loser[j];
				j++;
			}
		}
	}
	while(i<=idx){
		idx2++;
		athlete[idx2] = winner[i++];
	}
	while(j<=idx){
		idx2++;
		athlete[idx2] = loser[j++];
	}
}
int main(){
	cin>>n>>r>>q;
	for(int i=1;i<=2*n;i++){
		cin>>athlete[i].s;
		athlete[i].id=i;
	}
	for(int i=1;i<=2*n;i++){
		cin>>athlete[i].w;
	}
	sort(athlete+1,athlete+2*n+1,cmp);
	for(int i=1;i<=r;i++){
		merge();
	}
	cout<<athlete[q].id;
	return 0;
}