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| 1 | + |
| 2 | +#include <iostream> |
| 3 | +using namespace std; |
| 4 | + |
| 5 | +/* function to sort arr using shellSort */ |
| 6 | +int shellSort(int arr[], int n) |
| 7 | +{ |
| 8 | + // Start with a big gap, then reduce the gap |
| 9 | + for (int gap = n/2; gap > 0; gap /= 2) |
| 10 | + { |
| 11 | + // Do a gapped insertion sort for this gap size. |
| 12 | + // The first gap elements a[0..gap-1] are already in gapped order |
| 13 | + // keep adding one more element until the entire array is |
| 14 | + // gap sorted |
| 15 | + for (int i = gap; i < n; i += 1) |
| 16 | + { |
| 17 | + // add a[i] to the elements that have been gap sorted |
| 18 | + // save a[i] in temp and make a hole at position i |
| 19 | + int temp = arr[i]; |
| 20 | + |
| 21 | + // shift earlier gap-sorted elements up until the correct |
| 22 | + // location for a[i] is found |
| 23 | + int j; |
| 24 | + for (j = i; j >= gap && arr[j - gap] > temp; j -= gap) |
| 25 | + arr[j] = arr[j - gap]; |
| 26 | + |
| 27 | + // put temp (the original a[i]) in its correct location |
| 28 | + arr[j] = temp; |
| 29 | + } |
| 30 | + } |
| 31 | + return 0; |
| 32 | +} |
| 33 | + |
| 34 | +void printArray(int arr[], int n) |
| 35 | +{ |
| 36 | + for (int i=0; i<n; i++) |
| 37 | + cout << arr[i] << " "; |
| 38 | +} |
| 39 | + |
| 40 | +int main() |
| 41 | +{ |
| 42 | + int arr[] = {12, 34, 54, 2, 3}, i; |
| 43 | + int n = sizeof(arr)/sizeof(arr[0]); |
| 44 | + |
| 45 | + cout << "Array before sorting: \n"; |
| 46 | + printArray(arr, n); |
| 47 | + |
| 48 | + shellSort(arr, n); |
| 49 | + |
| 50 | + cout << "\nArray after sorting: \n"; |
| 51 | + printArray(arr, n); |
| 52 | + |
| 53 | + return 0; |
| 54 | +} |
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