Simplify Path

Given an absolute path for a file (Unix-style), simplify it.

For example,

path = "/home/", => "/home"path = "/a/./b/../../c/", => "/c"

栈法

复杂度

时间 O(N) 空间 O(N)

思路

思路很简单，先将整个路径按照/分开来，然后用一个栈，遇到..时弹出一个，遇到.和空字符串则不变，遇到正常路径则压入栈中。

注意

• 如果结果为空，要返回一个/

• 弹出栈时要先检查栈是否为空

代码

public class Solution {    public String simplifyPath(String path) {        Stack<String> stk = new Stack<String>();        String[] parts = path.split("/");        for(String part : parts){switch(part){    case ".":    case "" :        break;    case "..":        if(!stk.isEmpty()){stk.pop();        }        break;    default:        stk.push(part);}        }        StringBuilder sb = new StringBuilder();        if(stk.isEmpty()){return "/";        }        while(!stk.isEmpty()){sb.insert(0, "/"+stk.pop());        }        return sb.toString();    }}