mirror of https://github.com/TheAlgorithms/C
72 lines
1.4 KiB
C
72 lines
1.4 KiB
C
/**
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* @file
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* @brief [Insertion sort](https://en.wikipedia.org/wiki/Insertion_sort)
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* algorithm implementation.
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*/
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#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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/**
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* @addtogroup sorting Sorting algorithms
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* @{
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*/
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/**
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* Insertion sort algorithm implements using Recursion
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* @param arr array to be sorted
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* @param size size of array
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*/
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void RecursionInsertionSort(int *arr, int size)
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{
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if(size <= 0)
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{
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return;
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}
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// marking recursive call to reach starting element
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RecursionInsertionSort(arr,size-1);
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int key = arr[size-1];
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int j = size-2;
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// swapping logic for insertion sort
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while(j >= 0 && arr[j] > key)
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{
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arr[j+1] = arr[j];
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j--;
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}
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arr[j+1] = key;
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}
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/** @} */
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/** Test function
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* @returns None
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*/
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static void test()
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{
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const int size = rand() % 500; /* random array size */
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int *arr = (int *)calloc(size, sizeof(int));
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/* generate size random numbers from -50 to 49 */
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for (int i = 0; i < size; i++)
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{
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arr[i] = (rand() % 100) - 50;/* signed random numbers */
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}
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RecursionInsertionSort(arr, size);
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for (int i = 0; i < size ; ++i)
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{
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assert(arr[i] <= arr[i + 1]);
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}
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free(arr);
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}
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/** Main function
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* @returns integer 0
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*/
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int main(int argc, const char *argv[])
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{
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/* Intializes random number generator */
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srand(time(NULL));
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test();
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return 0;
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}
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