C :

#include <stdio.h>
#include <stdbool.h>
#include <math.h>


bool has_unique_digits(long long n);

int main() {
    
    long long min = ceil(sqrt(100000000)); 
    long long max = floor(sqrt(999999999));

    for (long long x = min; x <= max; x++) {
        long long square = x * x;
        if (has_unique_digits(square)) {
            printf("%lld\n", x);
        }
    }

    return 0;
}


bool has_unique_digits(long long n) {
    int digits[10] = { 0 }; 
    int count = 0; 

    while (n > 0) {
        int digit = n % 10; 
        if (digits[digit] > 0) 
            return false;
        digits[digit]++; 
        n /= 10; 
        count++; 
        if (count > 9) 
            return false;
    }

    return true; 
}

C++ :

#include <bits/stdc++.h>
#define int long long
using namespace std;
const int N=1e6+10;

int nums[15];

void solve()
{
	for(int i=10000;i<=35000;i++){
		for(int q=0;q<10;q++) nums[q]=0;
		int a=i*i;
		if(a>999999999) break;
		for(int j=1;j<=100000000;j*=10){
			nums[a/j%10]++;
		}
		for(int j=0;j<=10;j++){
			if(nums[j]>1) break;
			if(j==10) cout<<i<<" ";
		}
	}
}

signed main()
{
	ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	int t;
	t=1;
	while(t--)
	{
		solve();
	}
	return 0;
}