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J |
strcmp() Anyone? Input: Standard Input Output: Standard Output |
strcmp() is a library function in C/C++ which compares two strings. It takes two strings as input parameter and decides which one is lexicographically larger or smaller: If the first string is greater then it returns a positive value, if the second string is greater it returns a negative value and if two strings are equal it returns a zero. The code that is used to compare two strings in C/C++ library is shown below:
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int strcmp(char *s, char *t) |
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Figure: The standard strcmp() code provided for this problem. |
The number of comparisons required to compare two strings in strcmp() function is never returned by the function. But for this problem you will have to do just that at a larger scale. strcmp() function continues to compare characters in the same position of the two strings until two different characters are found or both strings come to an end. Of course it assumes that last character of a string is a null (\0) character. For example the table below shows what happens when than and that; therE and the are compared using strcmp() function. To understand how 7 comparisons are needed in both cases please consult the code block given above.
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t |
h |
a |
N |
\0 |
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t |
h |
e |
r |
E |
\0 |
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= |
= |
= |
≠ |
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= |
= |
= |
≠ |
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t |
h |
a |
T |
\0 |
t |
h |
e |
\0 |
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Returns negative value 7 Comparisons |
Returns positive value 7 Comparisons |
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Input
The input file contains maximum 10 sets of inputs. The description of each set is given below:
Each set starts with an integer N (0<N<4001) which denotes the total number of strings. Each of the next N lines contains one string. Strings contain only alphanumerals (0 9, A Z, a z) have a maximum length of 1000, and a minimum length of 1.
Input is terminated by a line containing a single zero. Input file size is around 23 MB.
Output
For each set
of input produce one line of output. This line contains the serial of output
followed by an integer T. This T denotes the total number of comparisons that
are required in the strcmp() function if all the strings are compared with one
another exactly once. So for N strings the function strcmp() will be called exactly
times. You have to
calculate total number of comparisons inside the strcmp() function in those calls. You can assume
that the value of T will fit safely in a 64-bit signed integer. Please note
that the most straightforward solution (Worst Case Complexity O(N2
*1000)) will time out for this problem.
Sample Input Output for Sample
Input
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2 a b 4 cat hat mat sir 0 |
Case 1: 1 Case 2: 6 |
Problem
Setter: Shahriar Manzoor, Special Thanks: