mirror of
https://github.com/frida/tinycc
synced 2024-12-22 13:12:34 +03:00
123 lines
3.3 KiB
C
123 lines
3.3 KiB
C
/* example from http://barnyard.syr.edu/quickies/hanoi.c */
|
|
|
|
/* hanoi.c: solves the tower of hanoi problem. (Programming exercise.) */
|
|
/* By Terry R. McConnell (12/2/97) */
|
|
/* Compile: cc -o hanoi hanoi.c */
|
|
|
|
/* This program does no error checking. But then, if it's right,
|
|
it's right ... right ? */
|
|
|
|
|
|
/* The original towers of hanoi problem seems to have been originally posed
|
|
by one M. Claus in 1883. There is a popular legend that goes along with
|
|
it that has been often repeated and paraphrased. It goes something like this:
|
|
In the great temple at Benares there are 3 golden spikes. On one of them,
|
|
God placed 64 disks increasing in size from bottom to top, at the beginning
|
|
of time. Since then, and to this day, the priest on duty constantly transfers
|
|
disks, one at a time, in such a way that no larger disk is ever put on top
|
|
of a smaller one. When the disks have been transferred entirely to another
|
|
spike the Universe will come to an end in a large thunderclap.
|
|
|
|
This paraphrases the original legend due to DeParville, La Nature, Paris 1884,
|
|
Part I, 285-286. For this and further information see: Mathematical
|
|
Recreations & Essays, W.W. Rouse Ball, MacMillan, NewYork, 11th Ed. 1967,
|
|
303-305.
|
|
*
|
|
*
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
|
|
#define TRUE 1
|
|
#define FALSE 0
|
|
|
|
/* This is the number of "disks" on tower A initially. Taken to be 64 in the
|
|
* legend. The number of moves required, in general, is 2^N - 1. For N = 64,
|
|
* this is 18,446,744,073,709,551,615 */
|
|
#define N 4
|
|
|
|
/* These are the three towers. For example if the state of A is 0,1,3,4, that
|
|
* means that there are three discs on A of sizes 1, 3, and 4. (Think of right
|
|
* as being the "down" direction.) */
|
|
int A[N], B[N], C[N];
|
|
|
|
void Hanoi(int,int*,int*,int*);
|
|
|
|
/* Print the current configuration of A, B, and C to the screen */
|
|
void PrintAll()
|
|
{
|
|
int i;
|
|
|
|
printf("A: ");
|
|
for(i=0;i<N;i++)printf(" %d ",A[i]);
|
|
printf("\n");
|
|
|
|
printf("B: ");
|
|
for(i=0;i<N;i++)printf(" %d ",B[i]);
|
|
printf("\n");
|
|
|
|
printf("C: ");
|
|
for(i=0;i<N;i++)printf(" %d ",C[i]);
|
|
printf("\n");
|
|
printf("------------------------------------------\n");
|
|
return;
|
|
}
|
|
|
|
/* Move the leftmost nonzero element of source to dest, leave behind 0. */
|
|
/* Returns the value moved (not used.) */
|
|
int Move(int *source, int *dest)
|
|
{
|
|
int i = 0, j = 0;
|
|
|
|
while (i<N && (source[i])==0) i++;
|
|
while (j<N && (dest[j])==0) j++;
|
|
|
|
dest[j-1] = source[i];
|
|
source[i] = 0;
|
|
PrintAll(); /* Print configuration after each move. */
|
|
return dest[j-1];
|
|
}
|
|
|
|
|
|
/* Moves first n nonzero numbers from source to dest using the rules of Hanoi.
|
|
Calls itself recursively.
|
|
*/
|
|
void Hanoi(int n,int *source, int *dest, int *spare)
|
|
{
|
|
int i;
|
|
if(n==1){
|
|
Move(source,dest);
|
|
return;
|
|
}
|
|
|
|
Hanoi(n-1,source,spare,dest);
|
|
Move(source,dest);
|
|
Hanoi(n-1,spare,dest,source);
|
|
return;
|
|
}
|
|
|
|
int main()
|
|
{
|
|
int i;
|
|
|
|
/* initialize the towers */
|
|
for(i=0;i<N;i++)A[i]=i+1;
|
|
for(i=0;i<N;i++)B[i]=0;
|
|
for(i=0;i<N;i++)C[i]=0;
|
|
|
|
printf("Solution of Tower of Hanoi Problem with %d Disks\n\n",N);
|
|
|
|
/* Print the starting state */
|
|
printf("Starting state:\n");
|
|
PrintAll();
|
|
printf("\n\nSubsequent states:\n\n");
|
|
|
|
/* Do it! Use A = Source, B = Destination, C = Spare */
|
|
Hanoi(N,A,B,C);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* vim: set expandtab ts=4 sw=3 sts=3 tw=80 :*/
|