再求助一次，求大佬解答..

感觉逻辑没问题，但是输出不来。

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

int tmp[1005],a[1005];

void paixu(int begin,int end,int mid){
    int i,u,p;
    i = begin;u = begin;p = mid; 
    while(i<mid&&p<=end){
        if(a[i]<a[p]) tmp[u++] = a[i++];
        else tmp[u++] = a[p++];
    }
    while(i<mid)tmp[u++] = a[i++];
    while(p<=end)tmp[u++] = a[p++];
    i = begin; p = begin;
    while(i<=end) a[i++] = tmp[p++]; 
}

void anssort(int begin,int end){
    int mid;mid = (begin+end)/2;
    if(mid<1)return;
    anssort(begin,mid);
    anssort(mid+1,end);
    paixu(begin,end,mid+1);
}

int main(){
    int n,k;
    cin >> n >> k;
    for(int i = 0; i < n; i++) cout<<a[i];
    anssort(a[0],a[n-1]);
    cout<<a[k];
    return 0;
}