71. Simplify Path
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 shortest string 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"
Example 5:
Input: "/a/../../b/../c//.//"
Output: "/c"
Example 6:
Input: "/a//b////c/d//././/.." Output: "/a/b/c"
题意：unix系统的路径简化
/** * @param {string} path * @return {string} */ var simplifyPath = function(path) { // 法一 // let v=[]; // let i=0; // while(i<path.length){ // while(path[i]==='/' && i<path.length) i++; // if(i===path.length) break; // let start=i; // while(path[i]!=='/' && i<path.length) i++; // let end=i-1; // let s=path.substr(start,end-start+1); // if(s==='..'){ // if(v.length>0) v.pop(); // }else if(s!=='.'){ // v.push(s); // } // } // if(v.length===0) return '/'; // let res=''; // for(let i=0;i<v.length;i++){ // res+='/'+v[i]; // } // return res; // 法二 return '/'+path.split('/').filter(str=> str!=='' && str!=='.').reduce((arr,str)=>{ if(str==='..') arr.pop(); else arr.push(str); return arr; },[]).join('/'); };