816. Ambiguous Coordinates

基本上這種string就是我的罩門, 我超不會處理的

看完李哥的詳解後

我們可以分成幾種case

s = "", 可以得到  {}
s = "0"          {s}
s = "0xxx0"      {}
s = "0xxx"       {0.XXX}
s = "xxx0"       {xxx}
s = "xxx"        {xxx, x.xx, xx.x}

所以我們拿掉頭尾, 然後用兩段去決定會出現的vector 字串

最後在兩者取一combine

class Solution {
public:
    vector<string> ambiguousCoordinates(string s) {
        int n = s.size();
        vector<string> res;
        for(int i = 0; i < n - 2;i++){
            vector<string> A = f(s.substr(1, i));
            vector<string> B = f(s.substr(i + 1, n - 2 - i));
            for(auto &a: A){
                for(auto &b: B){
                    string e = "(" + a + ", "+ b + ")";
                    res.push_back(e);
                }
            }
            
        }
        return res;
    }
    vector<string> f(string s){
        int n = s.size();
        if(n == 0 || (n > 1 && s[0] == '0' && s[n - 1] == '0')){
            return {};
        }
        if(n > 1 && s[0] == '0') return {"0." + s.substr(1)};
        if(n == 1 || s[n - 1] == '0') return {s};
        vector<string> res = {s};
        for(int i = 1; i < n; i++){
            res.push_back(s.substr(0, i) + '.' + s.substr(i));
        }
        return res;
    }
};