fork(1) download
copy 
  1. #include<stdio.h>
  2. #define DEFMAX 1000
  3. #include<stdlib.h>
  4. #include<string.h>
  5.  
  6. void printpalin(char *p,int *arr,int i,int len)
  7. {
  8. 	int k = i - len + 1,j;
  9.  
  10. 	for(j=k;j<i;j+=2)
  11. 		printf("%c",p[j/2]);
  12. 	for(j=i;j>=k;j-=2)
  13. 		printf("%c",p[j/2]);
  14. 	printf("\n");
  15. }
  16.  
  17. int calclen(char *p,int *arr,int cen,int n)
  18. {
  19. 	int k=(cen%2+1)%2+1,count=0,l=(cen-k)/2,r=(cen+k)/2;
  20. 	while(l>=0 && r<n && p[l]==p[r])
  21. 	{
  22. 		count+=2;
  23. 		l--;
  24. 		r++;
  25. 	}
  26. 	return count+k-1;
  27. }
  28.  
  29. int main()
  30. {
  31. 	int i,j,k,x,max=0,count=0,cen=0,set;
  32. 	char *p = malloc(sizeof(char)*DEFMAX),*temp=p;
  33. 	printf("enter string\n");
  34. 	scanf("%s",p);
  35. 	while(*temp++)count++;
  36. 	int *arr = malloc(sizeof(int)*(2*count-1));
  37.  
  38. 	while(cen<(2*count-1))
  39. 	{
  40. 		x=0;
  41. 		set =1;
  42. 		//printf("cen is %d\n",cen);	
  43. 		//get max palin length at center cen
  44. 		arr[cen] = calclen(p,arr,cen,count);
  45. 		//calculate next center
  46. 		for(k=1;k<=arr[cen]-2;k++)
  47. 		{
  48. 				if(arr[cen-k]<(arr[cen]-k))
  49. 					arr[cen+k] = arr[cen -k];
  50. 				else
  51. 					{
  52. 						cen+=k;
  53. 						set =0;
  54. 						break;
  55. 					}
  56. 		}
  57. 		if(set)
  58. 			cen++;
  59.  
  60. 	}
  61.  
  62. 	for(i=0;i<(2*count-1);i++)
  63. 	{
  64.  
  65. 		if(max<arr[i])
  66. 			max = arr[i];
  67. 	}
  68. 	printf("max length of the palindrome is %d\n",max);
  69. 	for(i=0;i<(2*count-1);i++)
  70. 	{
  71. 		if(max==arr[i])
  72. 			printpalin(p,arr,i,max);
  73. 	}
  74. 	return 0;
  75. }
  76.  
  77.  
stdin
copy 
abcbaba
compilation info 
prog.c: In function ‘main’:
prog.c:31: warning: unused variable ‘j’
prog.c:34: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result
stdout
copy 
enter string
max length of the palindrome is 5
abcba
https://ideone.com/aiG1m
language:
C (gcc 8.3)
created:
14 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!