In the Bucket Sorting technique, the data items are distributed in a set of buckets. Each bucket can hold a similar type of data. After distributing, each bucket is sorted using another sorting algorithm. After that, all elements are gathered on the main list to get the sorted form.
The complexity of the Bucket Sort Technique
Time Complexity: O(n + k) for best case and average case and O(n^2) for the worst case.
Space Complexity: O(nk) for worst case
Input and Output
Input: A list of unsorted data: 0.25 0.36 0.58 0.41 0.29 0.22 0.45 0.79 0.01 0.69 Array before Sorting: 0.25 0.36 0.58 0.41 0.29 0.22 0.45 0.79 0.01 0.69 Output: Array after Sorting: 0.01 0.22 0.25 0.29 0.36 0.41 0.45 0.58 0.69 0.79
Algorithm
bucketSort(array, size)
Input − An array of data, and the total number in the array
Output − The sorted Array
Begin for i := 0 to size-1 do insert array[i] into the bucket index (size * array[i]) done for i := 0 to size-1 do sort bucket[i] done for i := 0 to size -1 do gather items of bucket[i] and put in array done End
Example
#include<iostream> #include<vector> #include<algorithm> using namespace std; void display(float *array, int size) { for(int i = 0; i<size; i++) cout << array[i] << " "; cout << endl; } void bucketSort(float *array, int size) { vector<float> bucket[size]; for(int i = 0; i<size; i++) { //put elements into different buckets bucket[int(size*array[i])].push_back(array[i]); } for(int i = 0; i<size; i++) { sort(bucket[i].begin(), bucket[i].end()); //sort individual vectors } int index = 0; for(int i = 0; i<size; i++) { while(!bucket[i].empty()) { array[index++] = *(bucket[i].begin()); bucket[i].erase(bucket[i].begin()); } } } int main() { int n; cout << "Enter the number of elements: "; cin >> n; float arr[n]; //create an array with given number of elements cout << "Enter elements:" << endl; for(int i = 0; i<n; i++) { cin >> arr[i]; } cout << "Array before Sorting: "; display(arr, n); bucketSort(arr, n); cout << "Array after Sorting: "; display(arr, n); }
Output
Enter the number of elements: 10 Enter elements: 0.25 0.36 0.58 0.41 0.29 0.22 0.45 0.79 0.01 0.69 Array before Sorting: 0.25 0.36 0.58 0.41 0.29 0.22 0.45 0.79 0.01 0.69 Array after Sorting: 0.01 0.22 0.25 0.29 0.36 0.41 0.45 0.58 0.69 0.79