This is the right solution
Sorry for my english

var ans: array[1..1000] of longint;
n,m,y,q,i: longint;

function BinPow(x,y: longint): longint;
begin
  if y=1 then BinPow:=x
  else if y mod 2=0 then BinPow:=sqr(BinPow(x,y div 2)) mod M
  else BinPow:=(sqr(BinPow(x,y div 2))*x) mod M;
end;

begin
  readln(n,m,y);

  q:=0;

  for i:=0 to m-1 do
    begin
      if BinPow(i,n)=y then
      begin
        inc(q);
        ans[q]:=i;
      end;
    end;

  for i:=1 to q do
    write(ans[i],' ');

  if q=0 then writeln(-1);
end.

My solve in C++:
#include <iostream>
#include <string>
#include <vector>
#include <set>
#include <queue>
#include <map>
#include <stack>
#include <algorithm>
#include <bitset>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <cstdio>
#include <iomanip>

#define F first
#define S second
#define ll long long
#define len length()
#define sqr(x) x*x
#define pb push_back
#define mp make_pair
#define sz(x) ((int) (x).size())
#define all(x) x.begin(), x.end()
#define allr(x) x.rbegin(), x.rend()
#define bp(x) __builtin_popcount(x)
#define INF numeric_limits<long long int>::max()
#define frp freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout);
#define forit(it, s) for(__typeof(s.begin()) it = s.begin(); it != s.end(); it++)

const int maxn = (int)1e6;
const int mod = (int)1e9 + 7;

using namespace std;

__int64 n,m,y;

int binpow(int a, int n){
    if (n == 0)
        return 1;
    if (n % 2 == 1)
        return (binpow (a, n-1)*a)%m;
    else{
        int b = (binpow(a, n/2));
        return (b*b)%m;
    }
}

bool ok;

main(){
      scanf("%I64d%I64d%I64d",&n,&m,&y);
      for(int i=0; i < m; i++){
          if(binpow(i,n)%m==y){
              cout<<i<<" ";
              ok=1;
          }
      }
      if(!ok)
          return cout<<"-1",0;

    return 0;
}

What it is?
  else if y mod 2=0 then BinPow:=sqr(BinPow(x,y div 2)) mod M
  else BinPow:=(sqr(BinPow(x,y div 2))*x) mod M;