Given positive integers B and N, find an integer A such that A^N is as close as possible to B. (The result A is an approximation to the Nth root of B.) Note that A^N 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.

 1 #include <iostream> 2 #include <cmath> 3 #include <cstdlib> 4 using namespace std; 5 int main(){ 6     double b, n; 7     while(cin >> b >> n){ 8         if(b == 0 && n == 0) 9             break;10         //pow:double pow(double, double)11         int a = (int)pow(b, 1/ n);//直接取整，不是四舍五入 ,pow(a, n) < b12         if(b - pow(a, n) < pow(a + 1, n) - b)13             cout << a << endl;14         else15             cout << a + 1 << endl;16     }17     return 0;18 }

zoj 2818 Root of the Problem