UVa Problem 10077 The Stern-Brocot Number System （Stern-Brocot 代数系统）

// The Stern-Brocot Number System （Stern-Brocot 代数系统） // PC/UVa IDs: 110507/10077, Popularity: C, Success rate: high Level: 1 // Verdict: Accepted // Submission Date: 2011-05-29 // UVa Run Time: 0.016s // // 版权所有（C）2011，邱秋。metaphysis # yeah dot net // // 直接根据题意，定义3个分数，根据要求的分数与中间分数比较大小决定向左还是向右。 #include <iostream> using namespace std; struct fraction { long long unsigned numerator; long long unsigned denominator; }; int main(int ac, char *av[]) { long long unsigned up, down; fraction left, right, middle; while (cin >> up >> down, (up - down)) { left.numerator = 0; left.denominator = 1; right.numerator = 1; right.denominator = 0; middle.numerator = 1; middle.denominator = 1; while (1) { if (up * middle.denominator == down * middle.numerator) break; if (up * middle.denominator > down * middle.numerator) { cout << "R"; left.numerator = middle.numerator; left.denominator = middle.denominator; middle.numerator = (left.numerator + right.numerator); middle.denominator = (left.denominator + right.denominator); } else { cout << "L"; right.numerator = middle.numerator; right.denominator = middle.denominator; middle.numerator = (left.numerator + right.numerator); middle.denominator = (left.denominator + right.denominator); } } cout << endl; } return 0; }