蒟蒻TLE了，代码在线求调

#include<bits/stdc++.h>
using namespace std;
int tick,hunt,ans;
int a[5000005];
void merge_sort(int l,int r){
    if(l==r){
        ans=a[l];
        return;
    }

    int i=l,j=r,mid=a[(l+r)/2];
    do{
        while(a[j]>mid) j--;
        while(a[i]<mid) i++;
        if(i<=j){
            swap(a[i],a[j]);
            i++;
            j--;
        }
    }while(i<=j);
    if(hunt<=j) merge_sort(l,j);
    else if(i<=hunt) merge_sort(i,r);
    else merge_sort(j+1,i-1);
}
int main(){
    cin.tie();
    cout.tie();
    cin >> tick >> hunt; 
    for (int i=0;i<tick;i++) cin >> a[i];
    merge_sort(0,tick-1);
    cout << ans;
}