[LeetCode]Simplify Path

题目描述:(链接)

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

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

click to show corner cases.

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".

解题思路：

用栈。

class Solution {
public:
    string simplifyPath(string path) {
        vector<string> cache;
        for (auto i = path.begin(); i != path.end();) {
            ++i;
            auto j = find(i, path.end(), '/');
            auto sub = string(i, j);
            if (sub.size() > 0 && sub != ".") {
                if (sub == "..") {
                    if (!cache.empty()) {
                        cache.pop_back();
                    }
                } else {
                    cache.push_back(sub);
                }
            }
            i = j;
        }
        
        
        if (cache.empty()) {
            return string("/");
        }
        
        string result;
        for (auto str : cache) {
            result += "/";
            result += str;
        }
        
        return result;
    }
};