#include<iostream>
 
using namespace std;
 
#define MAX 1000005
 
int ans[MAX], count=0;
 
int solve(int X)
{
    //cout<<X<<endl;
    count++;
    if(ans[X]!=0){
        return ans[X];
    }
 
 
    int i, j, result=10*MAX, minResult = 10*MAX;
    if(X<2){
        return MAX*10;
    }
 
    result = solve(X-7) + 1;
    if(minResult > result){
        minResult = result;
    }
    result = solve(X-5) + 1;
    if(minResult > result){
        minResult = result;
    }
    result = solve(X-3) + 1;
    if(minResult > result){
        minResult = result;
    }
    result = solve(X-2) + 1;
    if(minResult > result){
        minResult = result;
    }
 
    ans[X] = minResult;
    //cout<<count<<" "<<X<<" = "<<ans[X]<<endl;
    return ans[X];
 
}
 
int main()
{
    int T;
    ans[2] = ans[3] = ans[5] = ans[7] = 1;
    cin>>T;
    while(T--)
    {
        int X, minstep=MAX*10;
        cin>>X;
        minstep = solve(X);
 
        if(minstep ==10*MAX )
            minstep=-1;
        cout<<minstep<<endl;
        //cout<<count<<endl;
 
    }
}

• Problem Description
  February Easy Challenge 2015 is underway. Hackerearth welcomes you all and hope that all you awesome coders have a great time. So without wasting much of the time let’s begin the contest.
  
  Prime Numbers have always been one of the favourite topics for problem setters. 
  
  Aishwarya is a mathematics student at the Department of Mathematics and Computing, California. Her teacher recently gave her an intriguing assignment with only a single question. The question was to find out the minimum number of single digit prime numbers which when summed equals a given number X.
  
  Input:
  The first line contains T denoting the number of test cases. Each of the next T lines contains a single integer X.
  
  Output:
  Print the minimum number required. If it is not possible to obtain X using single digit prime numbers, output -1.
  
  Constraints:
  1<=T<=100
  1<=X<=10^6
• Test Case 1
  Input (stdin)4
  7
  10
  14
  11
  Expected Output1
  2
  2
  3
• Test Case 2
  Input (stdin)3
  5688
  11126
  17529
  Expected Output814
  1590
  2505