CCF2016.4

思路：先把路径按反斜杠split成数组，然后用一个ArrayList去模拟。如果遇到空或者.则不处理；如果遇到..则删除ArrayList最后一个元素（注意如果只有1个元素则不删除）；其他情况直接加到ArrayList里面。注意特判输入空串的情况。

import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        int n = cin.nextInt();
        String curPath = cin.next();
        String[] curPathArr = curPath.split("/", -1);
        cin.nextLine();
        while (n-- > 0) {
            String path = cin.nextLine();
            if (path.length() == 0)
                System.out.println(curPath);
            else {
                String[] pathArr = path.split("/", -1);
                ArrayList<String> resultArr = new ArrayList<String>();
                int st = 1;
                if (pathArr[0].length() == 0)
                    resultArr.add("");
                else {
                    for (String s : curPathArr)
                        resultArr.add(s);
                    st = 0;
                }
                for (int i = st; i < pathArr.length; i++) {
                    if (pathArr[i].equals("..")) {
                        if (resultArr.size() > 1)
                            resultArr.remove(resultArr.size() - 1);
                    }
                    else if (!pathArr[i].equals(".") && !pathArr[i].equals(""))
                        resultArr.add(pathArr[i]);
                }
                if (resultArr.size() == 1)
                    System.out.println("/");
                else {
                    for (int i = 0; i < resultArr.size() - 1; i++)
                        System.out.print(resultArr.get(i) + "/");
                    System.out.println(resultArr.get(resultArr.size() - 1));
                }
            }
        }
    }
}