我把每个人的实力放在结构体里面发现答案会错，但是如果单独开一个数组去存放就正确了，这是为什么？

原代码如下

#include<bits/stdc++.h>
using namespace std;
const int MAXN = 2e6+5;
int N,R,Q;
struct Competitor
{
		int number;
		int store;
		int strength;
};
bool cmp(Competitor x,Competitor y)
{
	if(x.store == y.store)
	{
		return x.number < y.number;
	}
	return x.store > y.store;
}
Competitor arr[MAXN],win[MAXN],lose[MAXN];
int w[MAXN];//实力要单独写一个数组表示，否则答案错误 
void MergeSort()//归并排序 
{
	int i=1,j=1,k=1;
	while(i <= N && j <= N)
	{
		if(win[i].store > lose[j].store || (win[i].store == lose[j].store && win[i].number < lose[j].number))
		{
			arr[k].store = win[i].store;
			arr[k++].number = win[i++].number;
		}
		else
		{
			arr[k].store = lose[j].store;
			arr[k++].number = lose[j++].number;
		}
	}
	while(i <= N)
	{
		arr[k].store = win[i].store;
		arr[k++].number = win[i++].number;
	}
	while(j <= N)
	{
		arr[k].store = lose[j].store;
		arr[k++].number = lose[j++].number;
	}
}
int main()
{
	cin>>N>>R>>Q;
	for(int i = 1;i <= 2*N;i++)
	{
		cin>>arr[i].store;
		arr[i].number = i;
	}
	for(int i=1;i <= 2*N ; i++)
	{
		cin>>arr[i].strength;
	}
	sort(arr + 1 , arr + 1 + 2*N , cmp);
	while(R--)
	{
		int flag=1;
		for(int i = 1;i <= 2*N ;i+=2)
		{
			if(arr[i].number>arr[i+1].number)//胜者进胜组，败者进败组 
			{
				win[flag].store = arr[i].store+1;
				win[flag].number = arr[i].number;
				lose[flag].store = arr[i+1].store;
				lose[flag].number = arr[i+1].number;
				flag++;
			}
			else
			{
				win[flag].store = arr[i+1].store+1;
				win[flag].number = arr[i+1].number;
				lose[flag].store = arr[i].store;
				lose[flag].number = arr[i].number;
				flag++;
			}
		}
		MergeSort();
	}
	cout<<arr[Q].number;
    return 0;
}