docs+self-tests+lgtm fix

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Krishna Vedala 2020-07-10 23:19:24 -04:00
parent df25df3236
commit cfca2aba51
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@ -1,37 +1,85 @@
/**
* @file jump_search.c
* @brief Implementation of [jump
* search](https://en.wikipedia.org/wiki/Jump_search) algorithm.
*/
#include <assert.h>
#include <math.h> #include <math.h>
#include <stdio.h> #include <stdio.h>
/**
* @brief Macro to return the minimum of two values
*/
#define min(X, Y) ((X) < (Y) ? (X) : (Y)) #define min(X, Y) ((X) < (Y) ? (X) : (Y))
int jump_search(int *arr, int x);
int n;
int main() /**
{ * @brief Implement Jump-search algorithm
int arr[] = {0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610}; *
n = sizeof(arr) / sizeof(int); * @param [in] arr Array to search within
int x = 55; * @param x value to search for
int index = jump_search(arr, x); * @param n length of array
printf("\nNumber %d is at index %d\n", x, index); * @return index where the value was found
} * @return -1 if value not found
*/
int jump_search(int *arr, int x) int jump_search(const int *arr, int x, size_t n)
{ {
int step = floor(sqrt(n)); int step = floor(sqrt(n));
int prev = 0; int prev = 0;
while (*(arr + (min(step, n) - 1)) < x)
while (arr[min(step, n) - 1] < x)
{ {
prev = step; prev = step;
step += floor(sqrt(n)); step += floor(sqrt(n));
if (prev >= n) if (prev >= n)
{
return -1; return -1;
}
} }
while (*(arr + prev) < x) while (arr[prev] < x)
{ {
prev = prev + 1; prev = prev + 1;
if (prev == fmin(step, n)) if (prev == min(step, n))
{
return -1; return -1;
}
} }
if (*(arr + prev) == x) if (arr[prev] == x)
{
return prev; return prev;
}
return -1; return -1;
} }
/**
* @brief Test implementation of the function
*
*/
void test()
{
int arr[] = {0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610};
size_t n = sizeof(arr) / sizeof(int);
int x = 55;
printf("Test 1.... ");
int index = jump_search(arr, x, n);
assert(index == 10);
printf("passed\nTest 2.... ");
x = 56;
index = jump_search(arr, x, n);
assert(index == -1);
printf("passed\nTest 3.... ");
x = 13;
index = jump_search(arr, x, n);
assert(index == 7);
printf("passed\n");
}
/**
* @brief Main function
*/
int main()
{
test();
return 0;
}