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  • [leetcode]71. Simplify Path简化路径

    Given an absolute path for a file (Unix-style), simplify it. Or in other words, convert it to the canonical path.

    In a UNIX-style file system, a period . refers to the current directory. Furthermore, a double period .. moves the directory up a level. For more information, see: Absolute path vs relative path in Linux/Unix

    Note that the returned canonical path must always begin with a slash /, and there must be only a single slash / between two directory names. The last directory name (if it exists) must not end with a trailing /. Also, the canonical path must be the shorteststring representing the absolute path.

    Example 1:

    Input: "/home/"
    Output: "/home"
    Explanation: Note that there is no trailing slash after the last directory name.

    Example 2:

    Input: "/../"
    Output: "/"
    Explanation: Going one level up from the root directory is a no-op, as the root level is the highest level you can go.

    Example 3:

    Input: "/home//foo/"
    Output: "/home/foo"
    Explanation: In the canonical path, multiple consecutive slashes are replaced by a single one.

    Example 4:

    Input: "/a/./b/../../c/"
    Output: "/c"

    题意

    遇到"."的情况直接去掉,遇到".."删掉它上面挨着的一个路径, 求简化后的路径

    思路

    很接近real industry的题目

    将input通过/分离出来, 利用Stack来模拟遇到"."和".."的情况

     

    代码

     1 class Solution {
     2     public String simplifyPath(String path) {
     3         String[] arr = path.split("/");
     4         StringBuilder sb = new StringBuilder();
     5         Stack<String> stack = new Stack<>();
     6         
     7         for (int i = 0; i<arr.length; i++) {
     8             if (arr[i].equals("..")) {
     9                 if (!stack.isEmpty()) stack.pop();
    10             } else if (arr[i].equals(".")) {
    11                 continue;                
    12             } else if (!arr[i].isEmpty()) {
    13                 stack.push(arr[i]);
    14             }
    15         }
    16         
    17         if (stack.isEmpty()) return "/";
    18         
    19         // stack -> result String 
    20         while (!stack.isEmpty()) {
    21             sb.insert(0,  "/" + stack.pop());
    22         }     
    23         return sb.toString();      
    24     }
    25 }
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  • 原文地址:https://www.cnblogs.com/liuliu5151/p/10953072.html
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