Java算法

trim() 去除字符串两边的空格

split(" ") 用空格去切割字符串，返回一个字符串数组

字符串转整数

int i = Integer.parseInt([String])

整数转字符串

1.) String s = String.valueOf(i);

2.) String s = Integer.toString(i);

3.) String s = “” + i;

import java.util.Scanner;



//n个分数相加
public class Main {

    public static int Main(int x, int y){

        int z = 1;
        if(x>y){
            z = x;
            x = y;
            y = z;
        }
        for(int i=1;i<y;i++){

            if(x%i==0&&y%i==0){
                z = i;
            }

        }
        return z;

    }



    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        String str = in.next();
        String []a = str.split("/");
        int x = Integer.parseInt(a[0]);
        int y = Integer.parseInt(a[1]);



        for(int i=1;i<n;i++){
            String str1 = in.next();
            String []b = str1.split("/");
            int j = Integer.parseInt(b[0]);
            int k = Integer.parseInt(b[1]);
            x = x*k+j*y;
            y *= k;
            int l = Main(x,y);
            x /= l;
            y /= l;
        }
        if(y<0){
            x = -x;
            y = -y;
        }
        if(x%y==0) System.out.println(x/y);
        else if (x>y) System.out.println(x/y+" "+x%y+"/"+y);
        else System.out.println(x+"/"+y);

    }

}