阿里笔试(C++)

第一题和之前在leetcode上刷过的一题Word Break II有很多类似之处，感觉就是那道题改变了下？所以侥幸过了。
第二题没看懂题意，感觉自己很菜，不知有没有大神过了。这一贴一下第一题的代码：
#include <string>
#include <cstdio>
#include <set>
#include <algorithm>
#include <iostream>
#include <vector>
#include <unordered_map>
#include <unordered_set>
using namespace std;

/***
* ilikealibaba
* i like ali liba baba alibaba
**/
unordered_set<string> wordict;
unordered_map<string, vector<string>> map;

vector<string> wordscut(string s)
{
    if (map.find(s) != map.end())
        return map[s];
    vector<string> sens;
    for (int pos = s.size() - 1; pos >= 0; --pos)
    {
        string word = s.substr(pos);
        if (wordict.find(word) != wordict.end())
        {
            if (pos == 0) sens.push_back(word);
            else
            {
                vector<string> subSens = wordscut(s.substr(0, pos));
                for (auto subSens : subSens)
                    sens.push_back(subSens + " " + word);
            }
        }
    }
    map[s] = sens;
    return sens;
}

vector<string> helper(string s, const set<string> & Dict)
{
    wordict.insert(Dict.cbegin(), Dict.cend());
    return wordscut(s);
}

bool compare(string str1, string str2)
{
    return str1.length() < str2.length();
}

void mincut(const string& str, const set<string>& dict)
{
    int slen = str.length();
    int size = dict.size();
    if (size == 0)
    {
        cout << "n/a" << endl;
        return;
    }
    vector<string> res = helper(str, dict);
    if (res.empty())
    {
        cout << "n/a" << endl;
        return;
    }
    sort(res.begin(), res.end(), compare);
    cout << res[0] << endl;
}


int main(int argc, const char * argv[])
{
    string strS;
    string dictStr;
    int nDict;
    set<string> dict;

    cin >> strS;  //获取字符串
    cin >> nDict; //字典中词的个数
    for (int i = 0; i < nDict; i++)
    {
        cin >> dictStr;
        dict.insert(dictStr);
    }
    mincut(strS, dict);

    return 0;
}