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countiong.c
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countiong.c
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// #include <stdio.h>
// void countingSort(int a[],int freq[],int b[],int n){
// for(int i=0;i<n;i++){
// b[freq[a[i]]-1]=a[i];
// freq[a[i]]--;
// }
// }
// int main(){
// int n;
// printf("Enter the size of array: ");
// scanf("%d",&n);
// int a[n],freq[11]={0};
// int b[n];
// printf("Enter the elements:\n");
// for(int i=0;i<n;i++){
// printf("A[%d]: ",i);
// scanf("%d",&a[i]);
// freq[a[i]]++;
// b[i]=0;
// }
// for(int i=1;i<11;i++){
// freq[i]+=freq[i-1];
// }
// printf("The Unsorted Array:\n");
// for(int i=0;i<n;i++){
// printf("%d ",a[i]);
// }
// printf("\n");
// countingSort(a,freq,b,n);
// printf("The Sorted Array:\n");
// for(int i=0;i<n;i++){
// printf("%d ",b[i]);
// }
// printf("\n");
// return 0;
// }
// Counting sort in C programming
#include <stdio.h>
void countingSort(int array[], int size) {
int output[10];
// Find the largest element of the array
int max = array[0];
for (int i = 1; i < size; i++) {
if (array[i] > max)
max = array[i];
}
// The size of count must be at least (max+1) but
// we cannot declare it as int count(max+1) in C as
// it does not support dynamic memory allocation.
// So, its size is provided statically.
int count[10];
// Initialize count array with all zeros.
for (int i = 0; i <= max; ++i) {
count[i] = 0;
}
// Store the count of each element
for (int i = 0; i < size; i++) {
count[array[i]]++;
}
// Store the cummulative count of each array
for (int i = 1; i <= max; i++) {
count[i] += count[i - 1];
}
// Find the index of each element of the original array in count array, and
// place the elements in output array
for (int i = size - 1; i >= 0; i--) {
output[count[array[i]] - 1] = array[i];
count[array[i]]--;
}
// Copy the sorted elements into original array
for (int i = 0; i < size; i++) {
array[i] = output[i];
}
}
// Function to print an array
void printArray(int array[], int size) {
for (int i = 0; i < size; ++i) {
printf("%d ", array[i]);
}
printf("\n");
}
// Driver code
int main() {
int array[] = {4, 2, 2, 8, 3, 3, 1};
int n = sizeof(array) / sizeof(array[0]);
countingSort(array, n);
printArray(array, n);
}