71. Simplify Path

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problem

solution

先用split 切分成個字串，在判斷字串是否為”.” 或是 “..”

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class Solution {
public:
    vector<string> split(string str , char del ){
        vector<string> ret;
        string path ;
        for(char c:str){
            if(c==del){
                if(!path.empty()) ret.push_back(path);
                path="";
            }
            else path+=c;
        }
        if(!path.empty()) ret.push_back(path);
        return ret;
    }
    string simplifyPath(string path) {
        vector<string> str = split(path, '/');
        vector<string> ans;
        for(string tmp : str){
            if(tmp.empty()) continue;
            if(tmp == ".") continue;
            else if(tmp ==".."){
                if(!ans.empty()) ans.pop_back();
            }
            else ans.push_back(tmp);
        }
        string ret;
        for(string c:ans) ret+="/"+c;
        return ret.empty()?"/":ret;
    }
};

analysis

  • time complexity O(n)
  • space complexity O(n)