剑指offer习题集2

class Solution {
public:
     
    static bool compare(const string& s1, const string& s2) {  
        string t1 = s1 + s2;   
        string t2 = s2 + s1;
        return t1 <= t2? true : false;
    }
     
    string PrintMinNumber(vector<int> numbers) {
     
        string str;
        int i, len = numbers.size();   
        if (len<1) return str;
     
        string res;
        vector<string> vt;
        for (i = 0;i<len;++i) { 
            stringstream stream;       
            stream << numbers[i];    
            stream >> str;       
            vt.push_back(str);
        }
     
        sort(vt.begin(), vt.end(), compare);   
        for (i = 0;i<len;++i)       
            res += vt[i];  
        return res;
    }
};

class Solution
{
public:
    
    Solution():index(0){ //初始化位置
        for(int i=0;i<256;++i)
            pos[i]=-1;
    }
    
    
  //Insert one char from stringstream
    void Insert(char ch)
    {
         if(pos[ch]==-1)
             pos[ch]=index;
         else if(pos[ch]>=0)
             pos[ch]=-2;
             
         ++index;
    }
    
    
  //return the first appearence once char in current stringstream
    char FirstAppearingOnce()
    {  
        char res=‘#‘;
        int minv=1e8,i; //设置字符串max值
        for(i=0;i<256;++i){
            if(pos[i]>=0&&pos[i]<minv){ //若是当前位置小于min,则对min进行更新
                res=(char)i;
                minv=pos[i];
            }  
        }
        
        return res;
    }
    
private:
    int index;
    int pos[256];
};