Given positive integers B and N, find an integer A such that AN is as close as possible to B. (The result A is an approximation to the Nth root of B.) Note that AN may be less than, equal to, or greater than B.
Input: The input consists of one or more pairs of values for B and N. Each pair appears on a single line, delimited by a single space. A line specifying the value zero for both B and N marks the end of the input. The value of B will be in the range 1 to 1,000,000 (inclusive), and the value of N will be in the range 1 to 9 (inclusive).
Output: For each pair B and N in the input, output A as defined above on a line by itself.
Example Input: | Example Output: |
4 3 5 3 27 3 750 5 1000 5 2000 5 3000 5 1000000 5 0 0 | 1 2 3 4 4 4 5 16 |
Source: Mid-Central USA 2006
分析:
水题。
题意:
输入b和n,要求输出a^n-b绝对值最大的a(a为整数) 。
直接遍历a的值找到最接近的就行。指数的反函数是对数,所以很快就能确定a的值。
ac代码:
#include <iostream>
#include<cstdio>
#include<cmath>
using namespace std;
int main()
{
int n,b,i;
while(scanf("%d%d",&b,&n)&&b&&n)
{
for(i=1;;)
{
if(pow(i,n)<b)
i++;
else break;
}
if(pow(i,n)-b>b-pow(i-1,n))
printf("%d\n",i-1);
else printf("%d\n",i);
}
return 0;
}