HackerEarth Sorted String problem solution

In this HackerEarth Sorted String problem solution Little Ashish got a lot of strings as his birthday gift. He does not mind getting so many strings for free; in fact, he loves them. But, on noticing all the strings he received as a gift, Little Ashish, who's also a snob and a bit OCD kind of a guy, realizes that he does not like the way in which the strings are arranged.

He likes his strings sorted, in a different kind of a way. He wants his strings to be sorted based on the count of characters present in the string. For instance, if the string is: "aaabbc", then the desired string would be: cbbaaa. In case where the count of two characters is same, then the lexicographically smaller one will be printed first. For instance: "aabbcc" then, the output will be: "aabbcc".

HackerEarth Sorted String problem solution.

#include <bits/stdc++.h>
using namespace std;
#define f_in(st) freopen(st,"r",stdin);
#define f_out(st) freopen(st,"w",stdout);
int main()
{
  //f_in("in09.txt");
  //f_out("out09.txt");
  int test;
  cin>>test;
  while(test--)
  { 
    string s;
    cin>>s;
    vector<pair<int, int> > V(26);
    for(int i=0;i<26;i++){
      V[i].first=0;
      V[i].second=i;
    }
    for(int i=0;i<s.size();i++)
      V[s[i]-'a'].first++;
    sort(V.begin(),V.end());
    for(int i=0;i<26;i++)
    {
      int count=V[i].first;
      char ch=V[i].second+'a';
      for(int j=0;j<count;j++)
        cout<<ch;
    }
    cout<<endl;
  }
  return 0;
}

Second solution

#include<bits/stdc++.h>

using namespace std;

#define vi vector < int >
#define pii pair < int , int >
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define foreach(it,v) for( __typeof((v).begin())it = (v).begin() ; it != (v).end() ; it++ )
#define ll long long
#define llu unsigned long long
#define MOD 1000000007
#define INF 0x3f3f3f3f
#define dbg(x) { cout<< #x << ": " << (x) << endl; }
#define dbg2(x,y) { cout<< #x << ": " << (x) << " , " << #y << ": " << (y) << endl; }
#define all(x) x.begin(),x.end()
#define mset(x,v) memset(x, v, sizeof(x))
#define sz(x) (int)x.size()

char s[103];
int c[26];
bool cmp(char a,char b)
{
    if(c[a-'a'] == c[b-'a'])
        return a < b;
    return c[a-'a'] < c[b-'a'];
}
int main()
{
    int t,i;
    scanf("%d",&t);
    assert(1 <= t && t <= 100);
    while(t--)
    {
        scanf("%s",s);
        mset(c,0);
        for(i=0;s[i];i++)
        {
            assert('a' <= s[i] && s[i] <= 'z');
            c[s[i]-'a']++;
        }
        int n = i;
        assert(1 <= n && n <= 100);
        sort(s,s+n,cmp);
        printf("%s\n",s);
    }
    return 0;
}