[실5] 16395 - 파스칼의 삼각형

#pragma region 입출력 속도향상

#define FAST_IO() \
{\
	ios::sync_with_stdio(false);\
	cin.tie(NULL); \
	cout.tie(NULL); \
}\

#pragma endregion

#include <iostream>
#include <vector>

using namespace std;

int main()
{
	FAST_IO();

	int n, k;
	cin >> n >> k;

	vector<vector<int>> pascal(n);

	for (int i = 0; i < n; i++)
	{
		int val = 1;

		for (int k = 0; k <= i; k++)
		{
			pascal[i].push_back(val);
			val = val * (i - k) / (k + 1);
		}
	}
	cout << pascal[n - 1][k - 1];
	return 0;
}