Dice Summation

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef vector<ll> vl;
typedef pair<ll,ll> pl;


typedef long double C;
typedef complex<C> P;
#define X real()
#define Y imag()

#define sz(x) (ll)(x).size()

#define F first
#define S second
#define PB push_back
#define MP make_pair

#define REP(i,a,b) for (ll i = a; i < b; i++)

const ll mod = 1000000000+7;

const ll N = 1000000;

ll sum_c[N] = {0};

ll coin_sum(ll n) {
    if(sum_c[n] != 0) {
        return sum_c[n];
    }
    if(n == 0) {
        return 1;
    }
    ll c_sum = 0;
    ll min_n = min(n,(ll)6);
    REP(i,1,min_n+1) {
        //cout << i << endl;
        c_sum += (coin_sum(n-i))%mod;
    }
    sum_c[n] = c_sum;
    return c_sum;
}


int main() {
    ll n;
    cin >> n;

    cout << coin_sum(n)%mod << endl;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED