HDU4430：Yukari's Birthday(二分) - c++编程基础

Problem Description Today is Yukari's n-th birthday. Ran and Chen hold a celebration party for her. Now comes the most important part, birthday cake! But it's a big challenge for them to place n candles on the top of the cake. As Yukari has lived for such a long long time, though she herself insists that she is a 17-year-old girl.
To make the birthday cake look more beautiful, Ran and Chen decide to place them like r ≥ 1 concentric circles. They place k ⁱ candles equidistantly on the i-th circle, where k ≥ 2, 1 ≤ i ≤ r. And it's optional to place at most one candle at the center of the cake. In case that there are a lot of different pairs of r and k satisfying these restrictions, they want to minimize r × k. If there is still a tie, minimize r.

Input There are about 10,000 test cases. Process to the end of file.
Each test consists of only an integer 18 ≤ n ≤ 10 ¹².

Output For each test case, output r and k.
Sample Input

18
111
1111

Sample Output

1 17
2 10
3 10

题意：将蛋糕分作r个同心圆，圆心可以放一个或者不放蜡烛，然后同心圆从内到外，第i个同心圆放k^i个蜡烛，问r*k最小的时候，r,k的值分别是多少，r*k相同时，输出r最小的
思路：首先用等比数列求和公式估测出r最大的值为40左右，那么枚举r，并对k进行二分匹配答案即可

#include 
  
   
#include 
   
     #include 
    
      #include 
     
       using namespace std; #define ll __int64 ll n; ll bin(ll s) { ll l = 2,r = n,mid,i; while(l<=r) { mid = (l+r)/2; ll sum = 1,ans = 0;; for(i = 1; i<=s; i++) { if(n/sum
      
       n)//放置溢出 break; } if(ans == n || ans == n-1) return mid; else if(ans