Files
leetcode/apps/docs/content/(01-linear-structures)/binary-search/35_search-insert-position.mdx
T

72 lines
1.7 KiB
Plaintext

---
title: '35. Search Insert Position'
description: Given a sorted array of distinct integers 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
icon: dot
topics:
- { name: "Array", slug: "array" }
- { name: "Binary Search", slug: "binary-search" }
video: "K-RYzDZkzCI"
issue: "https://github.com/prdlk/leetcode/issues/63"
sidebar:
label: 'Search Insert Position'
badge: 'Easy'
---
::::warning
You must write an algorithm with O(log n) runtime complexity.
::::
### Example 1:
- Input: `nums = [1,3,5,6], target = 5`
- Output: `2`
### Example 2:
- Input: `nums = [1,3,5,6], target = 2`
- Output: `1`
### Example 3:
- Input: `nums = [1,3,5,6], target = 7`
- Output: `4`
### Constraints:
- `1 <= nums.length <= 10^4`
- `-10^4 <= nums[i] <= 10^4`
- `nums` contains distinct values sorted in ascending order.
- `-10^4 <= target <= 10^4`
## Approach
```mermaid
flowchart TD
S(["searchInsert(nums, target)"]) --> I["l = 0, r = n - 1"]
I --> W{"l <= r?"}
W -- yes --> M["m = (l + r) // 2"]
M --> Q{"nums[m] vs target"}
Q -- equal --> R(["return m"])
Q -- "nums[m] < target" --> L["l = m + 1"]
L --> W
Q -- "nums[m] > target" --> H["r = m - 1"]
H --> W
W -- no --> E(["return (l + r) // 2 + 1 — the insert slot"])
```
## Solution
```py
class Solution:
def searchInsert(self, nums: List[int], target: int) -> int:
l, r = 0, len(nums) - 1
while l <= r:
m = (l + r) // 2
if nums[m] == target:
return m
elif nums[m] < target:
l = m + 1
elif nums[m] > target:
r = m - 1
return (l + r) // 2 + 1
```