mirror of https://github.com/TheAlgorithms/C
56 lines
2.0 KiB
C
56 lines
2.0 KiB
C
#include <stdio.h>
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/* By comparison, binary search always chooses the middle of the remaining
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* search space, discarding one half or the other, depending on the comparison
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* between the key found at the estimated position and the key sought. The
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* remaining search space is reduced to the part before or after the estimated
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* position. The linear search uses equality only as it compares elements
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* one-by-one from the start, ignoring any sorting. On average the interpolation
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* search makes about log(log(n)) comparisons (if the elements are uniformly
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* distributed), where n is the number of elements to be searched. In the worst
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* case (for instance where the numerical values of the keys increase
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* exponentially) it can make up to O(n) comparisons. In
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* interpolation-sequential search, interpolation is used to find an item near
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* the one being searched for, then linear search is used to find the exact
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* item. */
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int interpolationSearch(int arr[], int n, int key)
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{
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int low = 0, high = n - 1;
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while (low <= high && key >= arr[low] && key <= arr[high])
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{
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/* Calculate the nearest posible position of key */
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int pos =
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low + ((key - arr[low]) * (high - low)) / (arr[high] - arr[low]);
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if (key > arr[pos])
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low = pos + 1;
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else if (key < arr[pos])
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high = pos - 1;
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else /* Found */
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return pos;
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}
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/* Not found */
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return -1;
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}
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int main()
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{
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int x;
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int arr[] = {10, 12, 13, 16, 18, 19, 20, 21, 22, 23, 24, 33, 35, 42, 47};
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int n = sizeof(arr) / sizeof(arr[0]);
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printf("Array: ");
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for (int i = 0; i < n; i++) printf("%d ", arr[i]);
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printf("\nEnter the number to be searched: ");
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scanf("%d", &x); /* Element to be searched */
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int index = interpolationSearch(arr, n, x);
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/* If element was found */
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if (index != -1)
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printf("Element found at position: %d\n", index);
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else
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printf("Element not found.\n");
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return 0;
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}
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