시간 제한메모리 제한제출정답맞힌 사람정답 비율
1 초 128 MB72441793149126.278%

문제

n개의 원소 중에서 k개를 순서 없이 선택하는 방법의 수는 몇 가지 일까?

입력

입력은 하나 또는 그 이상의 테스트 케이스로 이루어져 있다.

각 테스트 케이스는 한 줄로 이루어져 있으며, 231-1 을 넘지 않는 두 자연수 n(n ≥ 1)과 k(0 ≤ k ≤n)로 이루어져 있다.

입력의 마지막 줄에는 0이 두 개 주어진다.

출력

각 테스트 케이스에 대해서, 정답을 출력한다. 항상 정답이 231보다 작은 경우만 입력으로 주어진다.

예제 입력 1

4 2
10 5
49 6
0 0

예제 출력 1

6
252
13983816
W3sicHJvYmxlbV9pZCI6IjY1OTEiLCJwcm9ibGVtX2xhbmciOiIwIiwidGl0bGUiOiJcdWM3NzRcdWQ1NmQgXHVjMWZjXHViMmU0XHVjNmI0IiwiZGVzY3JpcHRpb24iOiI8cD5uXHVhYzFjXHVjNzU4IFx1YzZkMFx1YzE4YyBcdWM5MTFcdWM1ZDBcdWMxMWMga1x1YWMxY1x1Yjk3YyBcdWMyMWNcdWMxMWMgXHVjNWM2XHVjNzc0IFx1YzEyMFx1ZDBkZFx1ZDU1OFx1YjI5NCBcdWJjMjlcdWJjOTVcdWM3NTggXHVjMjE4XHViMjk0IFx1YmE4NyBcdWFjMDBcdWM5YzAgXHVjNzdjXHVhZTRjPzxcL3A+XHJcbiIsImlucHV0IjoiPHA+XHVjNzg1XHViODI1XHVjNzQwIFx1ZDU1OFx1YjA5OCBcdWI2MTBcdWIyOTQgXHVhZGY4IFx1Yzc3NFx1YzBjMVx1Yzc1OCBcdWQxNGNcdWMyYTRcdWQyYjggXHVjZjAwXHVjNzc0XHVjMmE0XHViODVjIFx1Yzc3NFx1YjhlOFx1YzViNFx1YzgzOCBcdWM3ODhcdWIyZTQuPFwvcD5cclxuXHJcbjxwPlx1YWMwMSBcdWQxNGNcdWMyYTRcdWQyYjggXHVjZjAwXHVjNzc0XHVjMmE0XHViMjk0IFx1ZDU1YyBcdWM5MDRcdWI4NWMgXHVjNzc0XHViOGU4XHVjNWI0XHVjODM4IFx1Yzc4OFx1YzczY1x1YmE3MCwgMjxzdXA+MzE8XC9zdXA+LTEgXHVjNzQ0IFx1YjExOFx1YzljMCBcdWM1NGFcdWIyOTQgXHViNDUwIFx1Yzc5MFx1YzVmMFx1YzIxOCBuKG4gJmdlOyAxKVx1YWNmYyBrKDAgJmxlOyBrICZsZTtuKVx1Yjg1YyBcdWM3NzRcdWI4ZThcdWM1YjRcdWM4MzggXHVjNzg4XHViMmU0LjxcL3A+XHJcblxyXG48cD5cdWM3ODVcdWI4MjVcdWM3NTggXHViOWM4XHVjOWMwXHViOWM5IFx1YzkwNFx1YzVkMFx1YjI5NCAwXHVjNzc0IFx1YjQ1MCBcdWFjMWMgXHVjOGZjXHVjNWI0XHVjOWM0XHViMmU0LjxcL3A+XHJcbiIsIm91dHB1dCI6IjxwPlx1YWMwMSBcdWQxNGNcdWMyYTRcdWQyYjggXHVjZjAwXHVjNzc0XHVjMmE0XHVjNWQwIFx1YjMwMFx1ZDU3NFx1YzExYywgXHVjODE1XHViMmY1XHVjNzQ0IFx1Y2Q5Y1x1YjgyNVx1ZDU1Y1x1YjJlNC4gXHVkNTZkXHVjMGMxIFx1YzgxNVx1YjJmNVx1Yzc3NCAyPHN1cD4zMTxcL3N1cD5cdWJjZjRcdWIyZTQgXHVjNzkxXHVjNzQwIFx1YWNiZFx1YzZiMFx1YjljYyBcdWM3ODVcdWI4MjVcdWM3M2NcdWI4NWMgXHVjOGZjXHVjNWI0XHVjOWM0XHViMmU0LjxcL3A+XHJcbiIsImhpbnQiOiIiLCJvcmlnaW5hbCI6IjAiLCJodG1sX3RpdGxlIjoiMCIsInByb2JsZW1fbGFuZ190Y29kZSI6IktvcmVhbiJ9LHsicHJvYmxlbV9pZCI6IjY1OTEiLCJwcm9ibGVtX2xhbmciOiIxIiwidGl0bGUiOiJCaW5vbWlhbCBTaG93ZG93biIsImRlc2NyaXB0aW9uIjoiPHA+SW4gaG93IG1hbnkgd2F5cyBjYW4geW91IGNob29zZSBrIGVsZW1lbnRzIG91dCBvZiBuIGVsZW1lbnRzLCBub3QgdGFraW5nIG9yZGVyIGludG8gYWNjb3VudD8mbmJzcDs8XC9wPlxyXG5cclxuPHA+V3JpdGUgYSBwcm9ncmFtIHRvIGNvbXB1dGUgdGhpcyBudW1iZXIuPFwvcD5cclxuIiwiaW5wdXQiOiI8cD5UaGUgaW5wdXQgZmlsZSB3aWxsIGNvbnRhaW4gb25lIG9yIG1vcmUgdGVzdCBjYXNlcy4mbmJzcDs8XC9wPlxyXG5cclxuPHA+RWFjaCB0ZXN0IGNhc2UgY29uc2lzdHMgb2Ygb25lIGxpbmUgY29udGFpbmluZyB0d28gaW50ZWdlcnMgbiAobiZndDs9MSkgYW5kIGsgKDAmbHQ7PWsmbHQ7PW4pLiZuYnNwOzxcL3A+XHJcblxyXG48cD5JbnB1dCBpcyB0ZXJtaW5hdGVkIGJ5IHR3byB6ZXJvZXMgZm9yIG4gYW5kIGsuPFwvcD5cclxuIiwib3V0cHV0IjoiPHA+Rm9yIGVhY2ggdGVzdCBjYXNlLCBwcmludCBvbmUgbGluZSBjb250YWluaW5nIHRoZSByZXF1aXJlZCBudW1iZXIuIFRoaXMgbnVtYmVyIHdpbGwgYWx3YXlzIGZpdCBpbnRvIGFuIGludGVnZXIsIGkuZS4gaXQgd2lsbCBiZSBsZXNzIHRoYW4gMjxzdXA+MzE8XC9zdXA+LjxcL3A+XHJcblxyXG48cD5XYXJuaW5nOiBEb24mIzM5O3QgdW5kZXJlc3RpbWF0ZSB0aGUgcHJvYmxlbS4gVGhlIHJlc3VsdCB3aWxsIGZpdCBpbnRvIGFuIGludGVnZXIgLSBidXQgaWYgYWxsIGludGVybWVkaWF0ZSByZXN1bHRzIGFyaXNpbmcgZHVyaW5nIHRoZSBjb21wdXRhdGlvbiB3aWxsIGFsc28gZml0IGludG8gYW4gaW50ZWdlciBkZXBlbmRzIG9uIHlvdXIgYWxnb3JpdGhtLiBUaGUgdGVzdCBjYXNlcyB3aWxsIGdvIHRvIHRoZSBsaW1pdC48XC9wPlxyXG4iLCJoaW50IjoiIiwib3JpZ2luYWwiOiIxIiwiaHRtbF90aXRsZSI6IjAiLCJwcm9ibGVtX2xhbmdfdGNvZGUiOiJFbmdsaXNoIn1d

출처

Contest > University of Ulm Local Contest > University of Ulm Local Contest 1997 B번