10696 - f91

Time limit: 3.000 seconds

http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=24&page=show_problem&problem=1637

Background

McCarthy is a famous theorician of computer science. In his work, he defined a recursive function, called f91, that takes as input a positive integer N and returns a positive integer defined as follows:

• If N ≤ 100, then f91(N) = f91(f91(N+11));
• If N ≥ 101, then f91(N) = N-10.

The Problem

Write a program, that computes McCarthy's f91.

The Input

The input tests will consist of a series of positive integers, each integer is at most 1,000,000. There will be at most 250,000 test cases. Each number is on a line on its own. The end of the input is reached when the number 0 is met. The number 0 shall not be considered as part of the test set.

Output

The program shall output each result on a line by its own, following the format given in the sample output.

Sample input

500 91 0

Sample output

f91(500) = 490 f91(91) = 91

完整代码：

/*0.078s*/

#include<cstdio>

int main(void)
{
	int N;
	while (scanf("%d", &N), N)
		if (N <= 100) printf("f91(%d) = 91\n", N);
		else printf("f91(%d) = %d\n", N, N - 10);
	return 0;
}