README.md

347. Top K Frequent Elements

Given a non-empty array of integers, return the k most frequent elements.

Example 1:

Input: nums = [1,1,1,2,2,3], k = 2 Output: [1,2] 

Example 2:

Input: nums = [1], k = 1 Output: [1] 

Note:

• You may assume k is always valid, 1 ≤ k ≤ number of unique elements.
• Your algorithm's time complexity must be better than O(n log n), where n is the array's size.
• It's guaranteed that the answer is unique, in other words the set of the top k frequent elements is unique.
• You can return the answer in any order.

Solutions (Rust)

1. Sort

use std::collections::HashMap;implSolution{pubfntop_k_frequent(nums:Vec<i32>,k:i32) -> Vec<i32>{letmut counter = HashMap::new();for num in nums {*counter.entry(num).or_insert(0) += 1;}letmut counter = counter.iter().collect::<Vec<_>>(); counter.sort_unstable_by_key(|c| c.1); counter .iter().rev().take(k asusize).map(|(k, v)| **k).collect()}}