Largest Number

Given a list of non negative integers, arrange them such that they form the largest number.

For example, given [3, 30, 34, 5, 9], the largest formed number is 9534330.

Note: The result may be very large, so you need to return a string instead of an integer.

 1 class Solution { 2 public: 3   4     static bool cmp(int a,int b) 5     { 6         int digitA=1; 7         int digitB=1; 8         9         int tmpA=a;10        11         while(tmpA>=10)12         {13             digitA++;14             tmpA/=10;15         }16        17         int tmpB=b;18         while(tmpB>=10)19         {20             digitB++;21             tmpB/=10;22         }23        24         return a*pow(10,digitB)+b>b*pow(10,digitA)+a;25        26     }27  28     string largestNumber(vector<int> &num) {29        30         sort(num.begin(),num.end(),cmp);31        32         string result="";33        34         for(int i=0;i<num.size();i++)  35         {36             result+=to_string(num[i]);37         }38        39         if(result[0]==‘0‘) result="0";40        41         return result;42        43     }44 };

 1 class Solution { 2 public: 3  4     static bool cmp(string a,string b) 5     { 6         return a+b>b+a; 7     } 8  9     string largestNumber(vector<int> &num) {10         11         int n=num.size();12         vector<string> strNum(n);13         for(int i=0;i<n;i++)14         {15             strNum[i]=to_string(num[i]);16         }17         18         sort(strNum.begin(),strNum.end(),cmp);19         20         string result="";21         22         for(int i=0;i<n;i++)23         {24             result+=strNum[i];25         }26         27         if(result[0]==‘0‘) result="0";28         29         return result;30     }31 };