백준 1699번 - C++

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

int D[100005];
int n;
int main(void) {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> n;
	D[1] = 1;
	for (int i = 2; i < 100001; i++) {
		D[i] = D[i - 1] + 1;
		int flag = 2;
		while (i - flag * flag >= 0) {
			D[i] = min(D[i], D[i - flag * flag] + 1);
			flag += 1;
		}
	}
	cout << D[n];
}