35. Search Insert Position

Stanislav Gumeniuk included in Leetcode Leetcode-Problem

2020-06-10 157 words One minute

Contents

Problem

Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.

You may assume no duplicates in the array.

example 1

Input: [1,3,5,6], 5
Output: 2

example 2

Input: [1,3,5,6], 2
Output: 1

example 3

Input: [1,3,5,6], 7
Output: 4

example 4

Input: [1,3,5,6], 0
Output: 0

Solution

Binary search

Using binary search with additional :

return 0 if target less then nums[0]
return len(nums) if target grater then nums[len(nums)-1]
where usually return -1 ( not exist element) – return left

func searchInsert(nums []int, target int) int {
    left := 0
    right:=len(nums)-1
    if target>nums[right] {
        return len(nums)
    }
    if target < nums[left] {
        return 0
    }
    for left<=right {
        med := (left+right)/2
        if nums[med] == target {
            return med
        }
        if nums[med]>target {
            right=med-1
            continue
        }
        if nums[med]<target {
            left=med+1
            continue
        }   
    }
    return left
}