poj 1190 TLE

using namespace std;
#include <vector>
#include <queue>
#include <algorithm>
#include <cmath>
#include <utility>
#include <bitset>
#include <set>
#include <string>
#include <stack>
#include <iomanip>
#include <map>

#define pb push_back
#define pii pair<int,int>
#define F first
#define S second
#define LL long long
#define mid (LB+RB)/2

const LL maxint64 = (1ll << 63) - 1;
const int maxint32 = (1ll << 31) - 1;

//iterators
#define iter(x) x.begin(),x.end()
#define aiter(a,n) a,a+n

//loops
#define REP(n) for (int ___=n;___--;)
#define REP0(i,n) for (int i=0;i<n;++i)
#define REP1(i,n) for (int i=1;i<=n;++i)
#define FOR(i,b,l,k) for (int i=b;i!=l;i+=k)
#define forEach(i,v) for (auto i:v)

/*
yungyao so weeeeeeeeeeeeeeeeeeeeeeeeeeak
8e7 so dian
FHVirus so dian
youou so dian
KYW so dian
hubert so dian
jass so dian
tingyu so dian
panda so dian
*/

//IO
#include <iostream>
#define theyRSOOOOOOOOODIAN ios_base::sync_with_stdio(false),cin.tie(0);
#define endl '\n'

//workspace

int m;
int hub,rub;

inline bool check(int i,LL h,LL r,int n){
    LL k = m - i;
    if (k)
        return (k+1) * r * r * h
        + k * (k+1) * (h*2*(r*6 + k*2 + 1) + r*r*6 + r*4*(k*2+1) + k*3*(k+1)) / 12
        <= n;
    else
        return r * r * h <= n;
}

int dfs(int i,int hb,int rb,int nleft){
    int minAns = 1e9;
    for (int h=hb;check(i,h,rb,nleft);++h){
        for (int r=rb;check(i,h,r,nleft);++r){
            if (i == m){
                if (r*r*h == nleft)
                    minAns = min(minAns,r*(r+h*2));
            }
            else{
                int dfsResult = dfs(i+1,h+1,r+1,nleft - r*r*h);
                if (dfsResult)
                    minAns = min(minAns,dfsResult + r*h*2);
            }
        }
    }
    return minAns == 1e9 ? 0 : minAns;
}

int main(){
    theyRSOOOOOOOOODIAN
    int n;

    cin >> n >> m;

    cout << dfs(1,1,1,n);

    return 0;
}