为什用快速选择算法会TLE

#include<bits/stdc++.h>
using namespace std;
int a[100005],temp;
int N,K;
inline int read()
{
    int x=0,f=1;
    char ch=getchar();
    while ((ch<'0' || ch>'9')&&ch!='-') ch=getchar();
    if (ch=='-')
        {
            f=0;
            ch=getchar();
        }
    while (ch>='0' && ch<='9')
        {
            x=(x<<3)+(x<<1)+ch-48;
            ch=getchar();
        }
    return f?x:-x;
}
inline int quickselect(int b,int e,int k)
{
    int i=b,j=e,mid=a[(i+j)>>1];
    while (i<=j)//注意,小于等于
        {
            while(a[i]<mid)i++;
            while(a[j]>mid)j--;
            if (i<=j)
                {
                    swap(a[i],a[j]);
                    i++;
                    j--;
                }
        }
    if (b<j&&k<=j)return quickselect(b,j,k);//分治
    if (i<e&&k>=i)return quickselect(i,e,k);
    return a[k];//如果不属于任何一方,就结束,返回
}
int main()
{
    N=read();
    for (int i=1; i<=N; i++)a[i]=read();
    cout<<a[1]<<endl;
    for(int i=3; i<=N; i+=2)cout<<quickselect(1,i,(i+1)/2)<<endl;
    return 0;
}