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Commit 8082f1c

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Merge branch 'master' of github.com:zwfang/leetcode
2 parents aeab9b4 + ebad4c1 commit 8082f1c

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‎README.md

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* [283. Move Zeroes(solution1)](./src/0283_move_zeroes/move_zeroes.go)   *`sliding window`*
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* [283. Move Zeroes(solution2)](./src/0283_move_zeroes/move_zeroes2.go)   *`sliding window`*
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* [303. Range Sum Query - Immutable](src/0303_range_sum_query/rsqim.go)
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* [347. Top K Frequent Elements](src/0347_top_k_frequent_elements/topkfe.go)   *`hash table;`*  *`heap`*
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* [349. Intersection of Two Arrays](./src/0349_intersection_of_2_arrays/intersection_of_two_arrays.go)   *`set`*
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* [350. Intersection of Two Arrays II](./src/0350_intersection_of_two_arrays2/intersection_of_two_arrays2.go)   *`hash table`*
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* [447. Number of Boomerangs](./src/0447_number_of_boomerangs/number_of_boomerangs.go)   *`hash table`*
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/*
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347. Top K Frequent Elements
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https://leetcode.com/problems/top-k-frequent-elements/
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Given a non-empty array of integers, return the k most frequent elements.
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Note:
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You may assume k is always valid, 1 ≤ k ≤ number of unique elements.
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Your algorithm's time complexity must be better than O(n log n), where n is the array's size.
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*/
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// time: 2019年01月08日
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package topkfe
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import "container/heap"
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// using priority
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// time complexity: O(n log n)
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// space complexity: O(n)
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func topKFrequent(nums []int, k int) []int {
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count := make(map[int]int)
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for _, num := range nums {
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if _, ok := count[num]; !ok {
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count[num] = 1
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} else {
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count[num]++
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}
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}
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nums_ := make(Nums, 0)
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for num, cnt := range count {
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nums_ = append(nums_, Num{Val: num, Count: cnt})
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}
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heap.Init(&nums_)
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var res []int
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for i := 0; i < k; i++ {
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num := heap.Pop(&nums_).(Num)
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res = append(res, num.Val)
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}
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return res
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}
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// Num stores its value and frequency as Count.
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type Num struct {
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Val int
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Count int
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}
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// Nums struct for impl Interface
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type Nums []Num
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// Len sort Interface
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func (n Nums) Len() int { return len(n) }
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// Swap sort Interface
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func (n Nums) Swap(i, j int) { n[i], n[j] = n[j], n[i] }
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// Less sort Interface
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func (n Nums) Less(i, j int) bool { return n[i].Count >= n[j].Count }
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// Push heap Interface
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func (n *Nums) Push(num interface{}) {
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m := num.(Num)
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*n = append(*n, m)
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}
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// Pop heap Interface
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func (n *Nums) Pop() interface{} {
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res := (*n)[len(*n)-1]
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*n = (*n)[:len(*n)-1]
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return res
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}
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package topkfe
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import (
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"reflect"
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"testing"
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)
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func TestTopKFrequent(t *testing.T) {
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nums := []int{1, 1, 1, 2, 2, 3}
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k := 2
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expected := []int{1, 2}
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if res := topKFrequent(nums, k); !reflect.DeepEqual(res, expected) {
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t.Errorf("expected %v, got %v", expected, res)
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}
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}

‎src/README.md

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|0343|[Integer Break](./0343_integer_break/integer_break.go)|Medium|*`recursion;`* *`memory search;`* *`dynamic programming`*|
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|0344|[344. Reverse String](0344_reverse_string/reverse_string.go)|Easy|*`double index`*|
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|0345|[345. Reverse Vowels of a String](0345_reverse_vowels_of_a_string/reverse_vowels.go)|Easy|*`double index`*|
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|0347|[347. Top K Frequent Elements](0347_top_k_frequent_elements/topkfe.go)|Medium|*`map;`* *`heap;`* *`array`*|
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|0349|[Intersection of Two Arrays](./0349_intersection_of_2_arrays/intersection_of_two_arrays.go)|Easy|*`set`*|
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|0350| [Intersection of Two Arrays II](./0350_intersection_of_two_arrays2/intersection_of_two_arrays2.go)|Easy|*`map`*|
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|0376|[Wiggle Subsequence](./0376_wiggle_subsequence/wiggle_subsequence.go)|Medium|*`dp`*|

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