[LeetCode] 71. Simplify Path

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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”.

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分析文件路径，其实通过’/’就是分割字符串，’/’之间的字符串分三种情况：

• s == “..”， 保存文件路径的栈的栈顶出栈。
• s == “.”， 什么都不做。
• s == 其他， 压栈。

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class Solution {public:    string simplifyPath(string path) {        vector<string> p;        int len = path.length();        string s = "";        for (int i=0; i<len; ++i) {            if (path[i] == '/') {                if (s == "..") {                    if (!p.empty()) {                        p.pop_back();                    }                } else if (s != "." && s != "") {                    p.push_back(s);                }                s = "";            } else {                s += path[i];            }        }        if (s == "..") {            if (!p.empty()) {                p.pop_back();            }        } else if (s != "." && s != "") {            p.push_back(s);        }        string res = "";        int psize = p.size();        for (int i=0; i<psize; ++i) {            res += "/" + p[i];        }        return res == "" ? "/" : res;    }};