HDU 4430 Yukari's Birthday

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <climits>
 7 #include <vector>
 8 #include <queue>
 9 #include <cstdlib>
10 #include <string>
11 #include <set>
12 #include <stack>
13 #define LL long long
14 #define pii pair<int,int>
15 #define INF 0x3f3f3f3f
16 using namespace std;
17 LL mypow(LL x,LL y){
18     LL ans = 1;
19     while(y){
20         if(y&1) ans *= x;
21         y >>= 1;
22         x *= x;
23     }
24     return ans;
25 }
26 int main() {
27     LL n,r,k,lt,rt,mid;
28     while(~scanf("%I64d",&n)){
29         r = 1;
30         k = n-1;
31         for(int i = 2; i <= 41; i++){
32             lt = 2;
33             rt = (LL)pow(n,1.0/i);
34             while(lt <= rt){
35                 mid = (lt+rt)>>1;
36                 LL sum = (mid-mypow(mid,i+1))/(1-mid);
37                 if(sum == n||sum == n-1){
38                     if(i*mid < r*k){
39                         r = i;
40                         k = mid;
41                     }
42                     break;
43                 }else if(sum < n) lt = mid+1;
44                 else rt = mid-1;
45             }
46         }
47         printf("%I64d %I64d\n",r,k);
48     }
49     return 0;
50 }