투포인터 활용, ugly numbers

#include <stdio.h>
#include <iostream>
#include <algorithm>
#include <vector>
#include <math.h>

using namespace std;

int a[1501];
int main() {
	//freopen("input.txt.txt","rt",stdin);
	int n, i, p2, p3, p5, min=INT_MIN;
	scanf("%d",&n);
	a[1]=1;
	p2=p3=p5=1;
	for(i=2; i<=n; i++){
		if(a[p2]*2 < a[p3]*3) min=a[p2]*2;
		else min=a[p3]*3;
		if(a[p5]*5<min) min=a[p5]*5;
		if(a[p2]*2==min) p2++;
		if(a[p3]*3==min) p3++;
		if(a[p5]*5==min) p5++;
		a[i] = min;
	}
	printf("%d",a[n]);
	
	
	return 0;	
}