[1일 1백준 : 1193번] 분수찾기

#include <iostream>

/*
1	2	6	7	15	16	28	29
3	5	8	14	17	27	30
4	9	13	18	26	31
10	12	19	25	32
11	20	24	33
21	23	34
22	35
36

1/1 -> 1/2 -> 2/1 -> 3/1 -> 2/2 -> 1/3 -> 2/2 -> 3/1 -> 4/1 -> 3/2 -> 2/3 -> 1/4 -> 1/5 -> 2/4 -> 3/3 -> 4/2 -> 5/1
*/

void FindFractionalNumber(const int X, int& numerator, int& denominator)
{
	bool IsReverse = true;
	int cnt = 0;

	if (X == 1) {
		numerator = denominator = 1;
	}
	else if (X == 2) {
		numerator = 1;
		denominator = 2;
	}

	for (decltype(cnt) i = 1; i <= X; i++)
	{
		if (IsReverse) {
			for (decltype(cnt) j = 1; j < i; j++)
			{
				//std::cout << j << "/" << i - j << " ";
				cnt++;

				if (cnt == X)
				{
					numerator = j;
					denominator = i - j;
					return;
				}
			}
			IsReverse = !IsReverse;
		}
		else {
			for (decltype(cnt) j = 1; j < i; j++)
			{
				//std::cout << i - j << "/" << j << " ";
				cnt++;

				if (cnt == X)
				{
					numerator = i - j;
					denominator = j;
					return;
				}
			}
			IsReverse = !IsReverse;
		}
		//std::cout << "\n";
	}
}


int main(void)
{
	std::cin.tie(NULL);
	std::cout.tie(NULL);
	std::ios::sync_with_stdio(false);

	int X = 0;
	
	//  분자			   분모
	int numerator = 0, denominator = 0;
	std::cin >> X;

	FindFractionalNumber(X, numerator, denominator);

	std::cout << numerator << "/" << denominator << "\n";

	return 0;
}

 

1193번: 분수찾기 (acmicpc.net)

1193번: 분수찾기