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LC - E - 796. Rotate String (sprintf, strstr)

Solutions in C

Solution 1

This solution uses C standard library string manipulation functions such as sprintf, strstr and strlen.

Complexity Analysis:

• $T=O(n)$$T = O(n)$ where $n$$n$ is the length of the given string s

• $S=O(1)$$S = O(1)$

Solution:

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#include <stdio.h>  // sprintf
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#include <string.h> // strstr, strlen
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bool rotateString(char * s, char * goal){
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    if (strlen(s) != strlen(goal))
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        return false;
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    // dynamically allocate memory for 'str' and initialize all bytes with 0 ('\0')
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    char *str = (char *)calloc(strlen(s) * 2 + 1, sizeof(char));
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    sprintf(str, "%s%s", s, s);
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    // thanks to 'calloc' the very last elelement of 'str' is already '\0'
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    if (strstr(str, goal) == NULL)
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        return false;
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    return true;
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}