# Leetcode 71 简化路径

leetcode第71题: 简化路径

https://leetcode.cn/problems/simplify-path/?envType=study-plan-v2&envId=top-interview-150

// 我的解法
string simplifyPath(string path)
{
    stack<string> s;
    // ./ ../ // 
    char dot = '.';
    char g = '/';
    string dir;
    bool flag = false;
    string pattern;
    string folder;
    for (int i = 0;i < path.size(); ++i)
    {
        if (path[i] == 'd')
            cout << "get into" << endl;
        if (i == 0 && path[i] == g)
            continue;
        if (path[i] == dot)
        {
            flag = true;
            pattern += dot;
            //continue;
        }
        if (flag && path[i] == '/')
        {
            if (pattern == LAST || pattern == CURRENT)
            {
                if (pattern == LAST)
                {
                    if (!s.empty())
                        s.pop();
                }
                // current直接delete
                flag = false;
                pattern.clear();
            }
            else {
                // 为 ....等其他形式
                s.push(folder);
                pattern.clear();
                folder.clear();
            }
            continue;
        }
        if (path[i] == '/')
        {
            if (!folder.empty())
            {
                s.push(folder);
                folder.clear();
            }
            continue;
        }
        folder += path[i];
    }
    if (pattern == LAST || pattern == CURRENT)
    {
        if (!s.empty() && pattern == LAST)
        {
            s.pop();
        }
        pattern.clear();
    }
    if (!pattern.empty())
        s.push(pattern);
    if (!folder.empty())
    {
        s.push(folder);
    }
        
    string res;
    while (!s.empty())
    {
        res = "/" + s.top() + res;
        s.pop();
    }
    return !res.empty() ? res : "/";
}

当你的循环已经非常复杂，逻辑已经很乱时，需要想当肯定是方法出现了问题，需要尽快转变思维，跳出来

// 实际借助字符分割很快就解决了
class Solution {
public:
    string simplifyPath(string path) {
        auto split = [](const string& s, char delim) -> vector<string> {
            vector<string> ans;
            string cur;
            for (char ch: s) {
                if (ch == delim) {
                    ans.push_back(move(cur));
                    cur.clear();
                }
                else {
                    cur += ch;
                }
            }
            ans.push_back(move(cur));
            return ans;
        };

        vector<string> names = split(path, '/');
        vector<string> stack;
        for (string& name: names) {
            if (name == "..") {
                if (!stack.empty()) {
                    stack.pop_back();
                }
            }
            else if (!name.empty() && name != ".") {
                stack.push_back(move(name));
            }
        }
        string ans;
        if (stack.empty()) {
            ans = "/";
        }
        else {
            for (string& name: stack) {
                ans += "/" + move(name);
            }
        }
        return ans;
    }
};