└── binary search


/binary search:
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 1 | // C++ program to implement iterative Binary Search
 2 | #include <bits/stdc++.h>
 3 | using namespace std;
 4 | 
 5 | // An iterative binary search function.
 6 | int binarySearch(int arr[], int l, int r, int x)
 7 | {
 8 | 	while (l <= r) {
 9 | 		int m = l + (r - l) / 2;
10 | 
11 | 		// Check if x is present at mid
12 | 		if (arr[m] == x)
13 | 			return m;
14 | 
15 | 		// If x greater, ignore left half
16 | 		if (arr[m] < x)
17 | 			l = m + 1;
18 | 
19 | 		// If x is smaller, ignore right half
20 | 		else
21 | 			r = m - 1;
22 | 	}
23 | 
24 | 	// If we reach here, then element was not present
25 | 	return -1;
26 | }
27 | 
28 | // Driver code
29 | int main(void)
30 | {
31 | 	int arr[] = { 2, 3, 4, 10, 40 };
32 | 	int x = 10;
33 | 	int n = sizeof(arr) / sizeof(arr[0]);
34 | 	int result = binarySearch(arr, 0, n - 1, x);
35 | 	(result == -1)
36 | 		? cout << "Element is not present in array"
37 | 		: cout << "Element is present at index " << result;
38 | 	return 0;
39 | }
40 | 


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