TOJ 1257 感受水题的力量

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

500910

Sample Output

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

Hint

Huge input and output, scanf( ) and printf( ) are recommended.

这道题的力量实在太大，开始不管是递归还是计算都WA。。。

结果发现输出很bug，不按常理出题而已

开始的想法是101-10=91 然后再89 90 91中找临界。后来想到了mod11的问题就简单了。

但是一直WA后，就暴力的用递归然后穷尽看。

然后发现。。。

#include<stdlib.h>#include<stdio.h>int main(){    int n = 0;    while(scanf("%d",&n)){        if(n==0)            break;        if(n>101){           printf("f91(%d) = %d\n",n,n-10);           continue;        }                else        {                     printf("f91(%d) = %d\n",n,91);           continue;        }           }    system("pause");    return 0;}