878239. Array Searching
Array Searching
Slug: search-an-element-in-an-array-1587115621--133819 Difficulty: Basic Id: 878239 Topic Tags: Arrays, Searching, Data Structures, Algorithms Company Tags: None
Summary
The problem involves searching for an element in an array. Given a sorted array and a target value, the task is to find the index of the target value if it exists in the array.
Detailed Explanation
To solve this problem, we can use a simple linear search algorithm. The basic idea is to iterate through the array, comparing each element with the target value until we find a match or reach the end of the array.
Here's a step-by-step breakdown of the solution:
- Initialize two pointers,
startandend, to represent the beginning and end of the array. - Calculate the middle index of the current range using the formula
(start + end) / 2. - Compare the element at the middle index with the target value.
- If the elements match, return the middle index as the result.
- If the target value is less than the middle element, update the
endpointer to the middle index minus one and repeat steps 2-4. - If the target value is greater than the middle element, update the
startpointer to the middle index plus one and repeat steps 2-4. - If the target value is not found after searching the entire array, return -1 (or a special value indicating that the element was not found).
Time complexity: O(n), where n is the length of the array.
Space complexity: O(1), as we only use a few extra variables to store the pointers and the middle index.
Optimized Solutions
Java
public int search(int[] nums, int target) {
int start = 0;
int end = nums.length - 1;
while (start <= end) {
int mid = start + (end - start) / 2;
if (nums[mid] == target) {
return mid;
}
if (target < nums[mid]) {
end = mid - 1;
} else {
start = mid + 1;
}
}
return -1; // not found
}