[sword finger offer] interview question 45: arrange the array into the smallest number

1. The higher number must be the smaller the better
2. The order of putting numbers must be first ( The leftmost one ) The smallest element , If the first digit is equal , Compare the second …, And so on .
3. If we convert all the numbers into strings and arrange them
4. Compare all strings
5. Two strings s1,s2 If s1+ s2 > s2 + s1 that s1 > s2
such as s1 by 3,s2 by 30, because s1+s2 = 330 ,s2+s1 = 303, therefore s1 > s2

Therefore, we can define string comparison rules by ourselves ：

static bool compare(string &s1, string &s2)
{
    
      return s1 + s2 < s2 + s1; 
}

adopt lambda Expressions can also be written .

The code is as follows ：

class Solution {
    
public:

    string minNumber(vector<int>& nums) {
    
        vector<string> strs;
        string result;
        for( int i = 0; i < nums.size(); i++)
        {
    
            strs.push_back(to_string(nums[i]));    
        }
        sort(strs.begin(), strs.end(), [](string &s1, string &s2) {
     return s1 + s2 < s2 + s1;} );
        //sort(strs.begin(), strs.end(), compare);
        for( int i = 0; i < strs.size(); i++ ) 
        {
    
            result += strs[i];
        }
        
        return result;

    }

    // static bool compare(string &s1, string &s2)
    // {
    
    // return s1 + s2 < s2 + s1; 
    // }
};

Make up the largest number
https://www.nowcoder.com/questionTerminal/fc897457408f4bbe9d3f87588f497729