[백준] 1373: 2진수 8진수

1373번: 2진수 8진수

#include <iostream>
#include <string>
using namespace std;

auto main()->int {
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr); cout.tie(nullptr);

	string in;
	cin >> in;
	int n = in.size();
	if (n % 3 == 1) {
		cout << in[0] - '0';
	}
	else if (n % 3 == 2) {
		cout << (in[0] - '0') * 2 + (in[1] - '0');
	}
	for (int i = n % 3; i < n; i += 3) {
		cout << (in[i] - '0') * 4 + (in[i + 1] - '0') * 2 + (in[i + 2] - '0');
	}

	cout << '\n';
}