[PAT] 1081 Rational Sum （20 分）Java

Given N rational numbers in the form numerator/denominator, you are supposed to calculate their sum.

Input Specification:

Each input file contains one test case. Each case starts with a positive integer N (≤100), followed in the next line N rational numbers a1/b1 a2/b2 ... where all the numerators and denominators are in the range of long int. If there is a negative number, then the sign must appear in front of the numerator.

Output Specification:

For each test case, output the sum in the simplest form integer numerator/denominator where integer is the integer part of the sum, numerator < denominator, and the numerator and the denominator have no common factor. You must output only the fractional part if the integer part is 0.

Sample Input 1:

5
2/5 4/15 1/30 -2/60 8/3

Sample Output 1:

3 1/3

Sample Input 2:

2
4/3 2/3

Sample Output 2:

2

Sample Input 3:

3
1/3 -1/6 1/8

Sample Output 3:

7/24

package pattest;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 * @Auther: Xingzheng Wang
 * @Date: 2019/2/26 21:26
 * @Description: pattest
 * @Version: 1.0
 */
public class PAT1081 {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String n = reader.readLine();
        String[] s1 = reader.readLine().split(" ");
        String[] s2 = s1[0].split("/");
        int a = Integer.parseInt(s2[0]), b = Integer.parseInt(s2[1]), sum = 0;
        for (int i = 1; i < Integer.parseInt(n); i++) {
            String[] s = s1[i].split("/");
            int atemp = Integer.parseInt(s[0]);
            int btemp = Integer.parseInt(s[1]);
            a = a * btemp + atemp * b;
            b = b * btemp;
            int c = GCD(a, b);
            a = a / c;
            b = b / c;
        }
        if (a % b == 0) {
            System.out.print(a / b);
        } else {
            if (Math.abs(a) > Math.abs(b)) {
                if (a > 0) {
                    System.out.printf("%d %d/%d", a / b, a - a / b * b, b);
                } else {
                    a = -a;
                    System.out.printf("-%d %d/%d", a / b, a - a / b * b, b);
                }
            } else {
                System.out.printf("%d/%d", a - a / b * b, b);
            }
        }
    }

    private static int GCD(int m, int n) {
        return n == 0 ? m : GCD(n, m % n);
    }
}