Leetcode:71. Simplify Path

Description

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

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

Corner Cases:

• Did you consider the case where path = "/../" In this case, you should return "/".
• Another corner case is the path might contain multiple slashes '/' together, such as "/home//foo/". In this case, you should ignore redundant slashes and return "/home/foo".

思路

• 实现一个函数，每一次返回一个文件夹或文件名
• 若是".."，则保存路径的vector从末尾删除一个，代表跳到上一级目录
• 若是"."，"/","" 则什么都不做
• 若是正常文件名，则存入vector

代码

class Solution {
public:
 string simplifyPath(string path) {
		vector<string> res;
		int len = path.size();
		if (len == 0) return path;

		int i = 0;
		while (i < len){
			string tmp = getNext(path, i, len);
			if (tmp == ".."){
				if (!res.empty()) res.pop_back();
			}
			else if (tmp == "." || tmp == "" || tmp == "/");
			else res.push_back(tmp);
		}


		int s = res.size();
		string str;
		for (i = 0; i < s; ++i){
			str += "/" + res[i];
		}
		return str == "" ? "/" : str;
	}

	string getNext(string& path, int &i, int len){
		string res;
		bool end = false;
		while (i < len){
			if (path[i] != '/')
				res += path[i++];
			else{

				if (end){
					break;
				}
				if (i + 1 < len && path[i + 1] == '/')
				{
					while (i + 1 < len && path[i + 1] == '/')
						i++;
				}
				i++;
				end = true;
			}
		}
		return res;

	}
};