SORTING & SEARCHING
SORTING TECHNIQUES
1) BUBBLE SORT
void bubbleSort(int arr[], int n)
{
int i,j,temp;
for (i=0;i<n-1;i++)
{
for (j=0;j<n-i-1;j++)
{
if (arr[j] > array[j+1])
{
int temp = arr[j];
array[j] = array[j+1];
array[j+1] = temp;
}
}
}
}
2) INSERTION SORT
void insertionSort(int arr[], int n)
{
int i, j, temp;
for (i = 1; i < n; i++)
{
temp = a[i];
j = i - 1;
while(j>=0 && temp <= a[j])
{
a[j+1] = a[j];
j = j-1;
}
a[j+1] = temp;
}
}
3) SELECTION SORT
void selection(int arr[], int n)
{
int i, j, small, temp;
for (i = 0; i < n-1; i++)
{
small = i;
for (j = i+1; j < n; j++)
{
if (arr[j] < arr[small])
small = j;
}
temp = arr[small];
arr[small] = arr[i];
arr[i] = temp;
}
}
4) MERGE SORT
#include <stdio.h>
#include <stdlib.h>
// Merges two subarrays of arr[].
// First subarray is arr[l..m]
// Second subarray is arr[m+1..r]
void merge(int arr[], int l, int m, int r)
{
int i, j, k;
int n1 = m - l + 1;
int n2 = r - m;
/* create temp arrays */
int L[n1], R[n2];
/* Copy data to temp arrays L[] and R[] */
for (i = 0; i < n1; i++)
L[i] = arr[l + i];
for (j = 0; j < n2; j++)
R[j] = arr[m + 1 + j];
/* Merge the temp arrays back into arr[l..r]*/
i = 0; // Initial index of first subarray
j = 0; // Initial index of second subarray
k = l; // Initial index of merged subarray
while (i < n1 && j < n2) {
if (L[i] <= R[j]) {
arr[k] = L[i];
i++;
}
else {
arr[k] = R[j];
j++;
}
k++;
}
/* Copy the remaining elements of L[], if there are any */
while (i < n1) {
arr[k] = L[i];
i++;
k++;
}
/* Copy the remaining elements of R[], if there are any */
while (j < n2) {
arr[k] = R[j];
j++;
k++;
}
}
/* l is for left index and r is right index of the sub-array of arr to be sorted */
void mergeSort(int arr[], int l, int r)
{
if (l < r) {
// Same as (l+r)/2, but avoids overflow for
// large l and h
int m = l + (r - l) / 2;
// Sort first and second halves
mergeSort(arr, l, m);
mergeSort(arr, m + 1, r);
merge(arr, l, m, r);
}
}
void printArray(int A[], int size)
{
int i;
for (i = 0; i < size; i++)
printf("%d ", A[i]);
printf("\n");
}
int main()
{
int arr[] = { 12, 11, 13, 5, 6, 7 };
int arr_size = sizeof(arr) / sizeof(arr[0]);
printf("Given array is \n");
printArray(arr, arr_size);
mergeSort(arr, 0, arr_size - 1);
printf("\nSorted array is \n");
printArray(arr, arr_size);
return 0;
}
5) QUICK SORT
#include <stdio.h>
#include <stdlib.h>
void swap(int* a, int* b)
{
int t = *a;
*a = *b;
*b = t;
}
/* This function takes last element as pivot, places the pivot element at its
correct position in sorted array, and places all smaller (smaller than pivot) to
left of pivot and all greater elements to right of pivot */
int partition (int arr[], int low, int high)
{
int pivot = arr[high]; // pivot
int i = (low - 1); // Index of smaller element and indicates the right position
of pivot found so far
for (int j = low; j <= high - 1; j++)
{
// If current element is smaller than the pivot
if (arr[j] < pivot)
{
i++; // increment index of smaller element
swap(&arr[i], &arr[j]);
}
}
swap(&arr[i + 1], &arr[high]);
return (i + 1);
}
/* The main function that implements QuickSort
arr[] --> Array to be sorted,
low --> Starting index,
high --> Ending index */
void quickSort(int arr[], int low, int high)
{
if (low < high)
{
/* pi is partitioning index, arr[p] is now
at right place */
int pi = partition(arr, low, high);
// Separately sort elements before
// partition and after partition
quickSort(arr, low, pi - 1);
quickSort(arr, pi + 1, high);
}
}
void printArray(int A[], int size)
{
int i;
for (i = 0; i < size; i++)
printf("%d ", A[i]);
printf("\n");
}
int main()
{
int arr[] = { 12, 11, 13, 5, 6, 7 };
int arr_size = sizeof(arr) / sizeof(arr[0]);
printf("Given array is \n");
printArray(arr, arr_size);
quickSort(arr, 0, arr_size - 1);
printf("\nSorted array is \n");
printArray(arr, arr_size);
return 0;
}
SEARCHING TECHNIQUES
1) LINEAR SEARCH
#include <stdio.h>
int linearSearch(int a[], int n, int val) {
// Going through array sequencially
for (int i = 0; i < n; i++)
{
if (a[i] == val)
return i+1;
}
return -1;
}
int main()
{
int a[] = {70, 40, 30, 11, 57, 41, 25, 14, 52}; // given array
int val = 41; // value to be searched
int n = sizeof(a) / sizeof(a[0]); // size of array
int res = linearSearch(a, n, val); // Store result
printf("The elements of the array are - ");
for (int i = 0; i < n; i++)
printf("%d ", a[i]);
printf("\nElement to be searched is - %d", val);
if (res == -1)
printf("\nElement is not present in the array");
else
printf("\nElement is present at %d position of array", res);
return 0;
}
2) BINARY SEARCH
#include <stdio.h>
int binarySearch(int a[], int beg, int end, int val)
{
int mid;
if(end >= beg)
{ mid = (beg + end)/2;
/* if the item to be searched is present at middle */
if(a[mid] == val)
{
return mid+1;
}
/* if the item to be searched is smaller than middle, then it can only be
in left subarray */
else if(a[mid] < val)
{
return binarySearch(a, mid+1, end, val);
}
/* if the item to be searched is greater than middle, then it can only be
in right subarray */
else
{
return binarySearch(a, beg, mid-1, val);
}
}
return -1;
}
int main() {
int a[] = {11, 14, 25, 30, 40, 41, 52, 57, 70}; // given array
int val = 40; // value to be searched
int n = sizeof(a) / sizeof(a[0]); // size of array
int res = binarySearch(a, 0, n-1, val); // Store result
printf("The elements of the array are - ");
for (int i = 0; i < n; i++)
printf("%d ", a[i]);
printf("\nElement to be searched is - %d", val);
if (res == -1)
printf("\nElement is not present in the array");
else
printf("\nElement is present at %d position of array", res);
return 0;
}
