diff --git a/leetcode/0347.Top-K-Frequent-Elements/347. Top K Frequent Elements.go b/leetcode/0347.Top-K-Frequent-Elements/347. Top K Frequent Elements.go
new file mode 100644
index 0000000..39be19b
--- /dev/null
+++ b/leetcode/0347.Top-K-Frequent-Elements/347. Top K Frequent Elements.go	
@@ -0,0 +1,29 @@
+package leetcode
+
+func TopKFrequentElements(nums []int, k int) []int {
+	bucket := make([][]int, len(nums))
+	freqTable := map[int]int{}
+	for _, num := range nums {
+		freqTable[num]++
+	}
+	for num, freq := range freqTable {
+		freq--
+		if bucket[freq] == nil {
+			bucket[freq] = make([]int, 0)
+		}
+		bucket[freq] = append(bucket[freq], num)
+	}
+	result := []int{}
+	count := 0
+	for i := len(bucket) - 1; i >= 0; i-- {
+		if bucket[i] == nil {
+			continue
+		}
+		result = append(result, bucket[i]...)
+		count += len(bucket[i])
+		if count == k {
+			break
+		}
+	}
+	return result
+}
diff --git a/leetcode/0347.Top-K-Frequent-Elements/347. Top K Frequent Elements_test.go b/leetcode/0347.Top-K-Frequent-Elements/347. Top K Frequent Elements_test.go
new file mode 100644
index 0000000..b348bae
--- /dev/null
+++ b/leetcode/0347.Top-K-Frequent-Elements/347. Top K Frequent Elements_test.go	
@@ -0,0 +1,48 @@
+package leetcode
+
+import (
+	"reflect"
+	"sort"
+	"testing"
+)
+
+// 填入 function input type
+type parameters0347 struct {
+	nums []int
+	k    int
+}
+
+func TestTopKFrequentElements(t *testing.T) {
+	tests := []struct {
+		parameters0347
+		// 填入 function output type
+		ans []int
+	}{
+		// 填入 test case
+		{
+			parameters0347{[]int{1, 1, 1, 2, 2, 3}, 2},
+			[]int{1, 2},
+		},
+		{
+			parameters0347{[]int{1}, 1},
+			[]int{1},
+		},
+		{
+			parameters0347{[]int{6, 6, 6, 0, 6, 6, 6}, 1},
+			[]int{6},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run("Test TopKFrequentElements", func(t *testing.T) {
+			// 完整輸入參數
+			result := TopKFrequentElements(test.parameters0347.nums, test.parameters0347.k)
+			// compare 的方式需視情況調整
+			sort.Ints(result)
+			sort.Ints(test.ans)
+			if !reflect.DeepEqual(result, test.ans) {
+				t.Errorf("TopKFrequentElements(%+v) got %+v, want %+v", test.parameters0347, result, test.ans)
+			}
+		})
+	}
+}
diff --git a/leetcode/0347.Top-K-Frequent-Elements/README.md b/leetcode/0347.Top-K-Frequent-Elements/README.md
new file mode 100644
index 0000000..86a7bbb
--- /dev/null
+++ b/leetcode/0347.Top-K-Frequent-Elements/README.md
@@ -0,0 +1,23 @@
+# 347. Top K Frequent Elements
+
+<https://leetcode.com/problems/top-k-frequent-elements/>
+
+給定整數陣列 `nums` 和整數 `k`  
+回傳 `nums` 中前 `k` 個高頻率出現的數字  
+回傳的數字可以用任何順序出現  
+答案已保證是獨一無二的，且要求時間複雜度必須優於 $O(n \cdot log(n))$
+
+假設 `nums` 長度是 `n`  
+則出現頻率最高的次數也就是 `n`，意思是「頻率」數值的範圍有限  
+因此，可以建立一個長度為 `n` 的 bucket，將相應出現頻率的數字放到指定的 index  
+
+一開始先用 $O(n)$ 掃 `nums` 將所有數字及其頻率記錄在 hash table  
+接著掃一次這個 hash table，將出現頻率記錄在相應 bucket  
+最後從 bucket 的最後取出前 `k` 個 element
+
+這樣子的時間和空間複雜度都只需要 $O(n)$
+
+## Takeaway
+
+- Hash Table
+- Counting Sort