Search Insert Position
To solve this coding challenge, let's break down the problem and understand the requirements and constraints in detail before moving into the pseudocode solution.
Explanation
The task is to find the position at which a target value should be inserted into a sorted array of distinct integers if it is not already present in the array. If the target is present, we should simply return its index. We are required to implement this with a time complexity of \(O(\log n)\), indicating the use of a binary search approach.Problem Breakdown:
- Input Description:
-
A sorted array
of distinct integers.
nums -
An integer
.
target - Output Description:
- The index if the target is found.
- The index where the target would be inserted to maintain sorted order if the target is not found.
- Constraints:
-
Array
is sorted in ascending order.
nums -
Array
contains distinct integers, so no duplicates are present.
nums - Target and elements of the array are bounded by the range -10^4 to 10^4.
- Array length ranges from 1 to 10^4.
-
Initialize two pointers,
and
left, to the start (0) and end (length of the array - 1) of the array.right -
While the
pointer does not exceed the
leftpointer:right -
Calculate the middle index,
.
mid -
Compare the
with the middle element
target:nums[mid] -
If
equals
nums[mid], returntarget.mid -
If
is greater than
target, move thenums[mid]pointer toleft.mid + 1 -
If
is less than
target, move thenums[mid]pointer toright.mid - 1 -
If the loop exits without finding the target, the
pointer will point to the insertion position where the target can be inserted in order.
left - Initialization:
-
and
leftvariables are initialized to point to the first and last index of the array, respectively.right - Binary Search Loop:
-
This loop continues as long as
is less than or equal to
left.right -
is recalculated in each iteration to find the middle index of the current search range.
mid - Comparison and Adjustment of Search Range:
-
If the middle element equals the target, return
.
mid -
If the target is greater than the middle element, narrow the search to the right half by setting
to
left.mid + 1 -
If the target is less than the middle element, narrow the search to the left half by setting
to
right.mid - 1 - Insertion Position:
-
If the loop exits without finding the target,
will be the insertion point.
left
Approach:
Given the requirement of \(O(\log n)\) time complexity, we will use a binary search algorithm. Binary search reduces the search range by half at each step, allowing us to efficiently find the target or the appropriate insertion position.High-Level Steps:
Detailed Steps in Pseudocode:
function searchInsert(nums, target):
# Initialize pointers for the binary search
left = 0
right = length of nums - 1
# Binary search loop
while left <= right:
# Calculate the middle index
mid = left + (right - left) // 2
# Check if the middle element is the target
if nums[mid] == target:
return mid # Target found, return the index
# If target is greater than middle element, search in the right half
elif nums[mid] < target:
left = mid + 1
# If target is less than middle element, search in the left half
else:
right = mid - 1
# If we exit the loop, left is the insertion point
return left
Explanation of Pseudocode:
left = 0
right = length of nums - 1
while left <= right:
mid = left + (right - left) // 2
if nums[mid] == target:
return mid
elif nums[mid] < target:
left = mid + 1
else:
right = mid - 1
return left