whust 2016 warm up G ||codeforces 689C. Mike and Chocolate Thieves

 1/* ***********************************************
 2Author :111qqz
 3Created Time :2016年07月18日 星期一 15时58分55秒
 4File Name :code/2016whust/G.cpp
 5************************************************ */
 6
 7#include <cstdio>
 8#include <cstring>
 9#include <iostream>
10#include <algorithm>
11#include <vector>
12#include <queue>
13#include <set>
14#include <map>
15#include <string>
16#include <cmath>
17#include <cstdlib>
18#include <ctime>
19#define fst first
20#define sec second
21#define lson l,m,rt<<1
22#define rson m+1,r,rt<<1|1
23#define ms(a,x) memset(a,x,sizeof(a))
24typedef long long LL;
25#define pi pair < int ,int >
26#define MP make_pair
27
28using namespace std;
29const double eps = 1E-8;
30const int dx4[4]={1,0,0,-1};
31const int dy4[4]={0,-1,1,0};
32const int inf = 0x3f3f3f3f;
33LL m,n;
34LL ans;
35LL cal( LL x)
36{
37    LL res = 0LL;
38    for ( LL i =2 ; i * i * i <= x ; i++)
39	res+=x/(i*i*i);
40    return res;
41}
42int main()
43{
44	#ifndef  ONLINE_JUDGE 
45	freopen("code/in.txt","r",stdin);
46  #endif
47
48	cin>>m;
49	n = 0 ;
50
51	LL cur = 1LL<<60;
52//	cout<<"cur:"<<cur<<endl;
53	while (cur!=0LL)
54	{
55	    LL tmp = cal(n+cur);
56	    if (tmp<m) n +=cur;
57
58	    cur >>=1LL;
59	}
60	n++;
61//	cout<<" n:"<<n<<endl;
62	if (cal(n)!=m) ans = -1;
63	else ans =  n;
64
65	cout<<ans<<endl;
66
67
68  #ifndef ONLINE_JUDGE  
69  fclose(stdin);
70  #endif
71    return 0;
72}