CareerCup

What is the output for below string
i/p==abcd
o/p==adbc

If only the number of moves is asked,
operations = number of chars in wrong position precisely.

Though questions does not seems clear to me. I assume that you want to convert one string to another by rotating it.

In this case append first string with itself and find index of start of the second string in it. That is the no of shifts required.

For the above example, we will scan both the strings and as soon as we encounter a non-matching character(in above example b and d). we'll store these two characters. Now in string 1(i/p string) we'll find the position of b and d and subtract them to get the number of required shifts. So number of shifts will be 2.
Hence the answer : 2.

Please correct me if the solution fails for any case.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char** argv)
{
	if (argc != 3)
	{
		Usage();
	}
	else
	{
		char* s1 = argv[1];
		char* s2 = argv[2];

		if (strlen(s1) != strlen(s2))
		{
			printf("the two string don't have the same size : \n %s -> %d \n %s -> %d", s1, strlen(s1) , s2, strlen(s2));
		}
		else
		{
			int i = 0;
			int shift = 0;
			while(i < strlen(s1) )
			{
				int isexisting = find(i, s1, s2);

				if (isexisting != -1)
				{
					s2[isexisting] = ' ';// replace a used charcter in a string by a space in order to don't reuse it

					if (isexisting != i)
					{
						shift++;
					}
				}
				else
				{
					printf("2 strings don't match");
					return 0;
				}

				i++;
			}
			printf("shift number: %d\n", shift/2);
		}
	}
	return 0;
}

void Usage()
{
	printf("\n ./NeededShift \"string1\" \"string2\" \n");
}

//find s1[pos] in s2 return -1 if not found 
int find(int pos, char* s1, char* s2)
{
	int i = 0;

	while(i < strlen(s2))
	{
		if (s1[pos] == s2[i])
		{
			return i;
		}
		i++;
	}
	return -1;
}

Levenshtein Distance algorithm can be applied to find the distance between two strings.

If space is not an issues, then
1.Scan the original string and store the positions as values in the hash.
2.Now scan the next string and for each char, get the absolute difference of disntace of
the first string char from hast table and the current position.
3.Sum all distances.