missing number solution added
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{
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// Use IntelliSense to learn about possible attributes.
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// Hover to view descriptions of existing attributes.
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// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
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"version": "0.2.0",
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"configurations": []
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}
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[package]
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name = "missing_number"
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version = "0.1.0"
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edition = "2021"
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# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
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[dependencies]
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# Comments on the solution
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We are using a simple mathematical approach that it's pretty much self-explanatory. We can express the sum of all numbers from `0` to `n` as `n * (n + 1) / 2`. We can then subtract the sum of the array from the sum of all numbers from `0` to `n` to get the missing number.
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### Complexity
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- **Time Complexity:** `O(n)` - We are iterating over the array once.
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- **Space Complexity:** `O(1)` - We are not using any extra space.
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---
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### Solution in Rust
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```rust
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fn missing_number(nums: Vec<i32>) -> i32 {
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(1..=nums.len() as i32).sum::<i32>() - nums.iter().sum::<i32>()
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}
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```
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where we use the `..=` range operator to create a range from `1` to the length of the input vector, and then sum the values in that range using the `sum` method
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### Leetcode result
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![](https://i.imgur.com/qW2tNVm.png)
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// Given an array nums containing n distinct numbers in the range [0, n], return the only number in the range that is missing from the array.
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fn missing_number(nums: Vec<i32>) -> i32 {
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(1..=nums.len() as i32).sum::<i32>() - nums.iter().sum::<i32>()
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}
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fn main() {
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let nums = vec![3, 0, 1];
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println!("{}", missing_number(nums));
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}
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