Equilateral numbers

#include <bits/stdc++.h>

#define ll long long

using namespace std;

ll func(ll n){
    ll res = 0;
    if(n==1){ 
        res=1;
    }
    if(n==3){ 
        res=1;
    }
    if(n==6){ 
        res=1;
    }
    if(res == 0){
        for(ll i=0; i < n; i++){
            
            if(n==i*(i+1)){
                res = 2;
                break;
            }
            if(n==((i*(i+1))/2)){ 
                res = 1;
                break;
            }
            if(n > ((i*(i+1))/2) && n < (((i+1)*(i+2))/2)){
                res = 1+func(n-((i*(i+1))/2));
                break;
            }
        }
    }
    return res;
}

int main(){
    ll n;
    cin >> n;
    ll res = 0;
    res = func(n);   

    cout << res << "\n";
    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: ACCEPTED

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: WRONG ANSWER