Hackerearth Balance strings Solution

PROBLEM STATEMENT:

Balance strings, by definition, are the strings that contain all the characters of the alphabet, from a to z, equal no of times. eg- abcdefghijklmnopqrstuvwxyz is a balanced string, aabb is not.

Input:
First line contains number of test cases T. Each test case contains a string S which made up of only lowercase characters.

Output:
For each test case print Yes if the string is balanced string else print No.

Constraints:
1<=T<=10
1<=|S|<=1000

SOURCE CODE:

 #include <iostream>  
 using namespace std;  
 int main()  
 {  
   int t;  
   cin>>t;  
   while(t--){  
        char arr[10000];  
        int a[500]={0},mx=0;  
        cin>>arr;  
        for(int i=0;arr[i]!='\0';i++){  
             int temp = arr[i]-97;  
             a[temp]++;  
             if(a[temp]>mx){  
                  mx = a[temp];  
             }  
        }  
        int flag = 1;  
        for(int i=0;i<26;i++){  
             if(a[i]!=mx){  
                  flag = 0;  
             }  
        }  
        if(flag)  
        {  
             cout<<"Yes"<<endl;  
        }  
        else{  
             cout<<"No"<<endl;  
        }  
   }  
   return 0;  
 }  

** The above solution is my own code and it may not be the optimal solution or optimal way to approach the problem but it passes all the testcases in Hackerearth. So if you have any optimal approaches feel free to paste the code as the comment below..... :) :) :)