Add solution and test-cases for problem 981

leetcode/901-1000/0981.Time-Based-Key-Value-Store/README.md

@@ -1,28 +1,32 @@
 # [981.Time Based Key-Value Store][title]
 
-> [!WARNING|style:flat]
-> This question is temporarily unanswered if you have good ideas. Welcome to [Create Pull Request PR](https://github.com/kylesliu/awesome-golang-algorithm)
-
 ## Description
+Design a time-based key-value data structure that can store multiple values for the same key at different time stamps and retrieve the key's value at a certain timestamp.
 
-**Example 1:**
-
-```
-Input: a = "11", b = "1"
-Output: "100"
-```
+Implement the `TimeMap` class:
 
-## 题意
-> ...
+- `TimeMap()` Initializes the object of the data structure.
+- `void set(String key, String value, int timestamp)` Stores the `key` key with the `value` value at the given time `timestamp`.
+- `String get(String key, int timestamp)` Returns a value such that `set` was called previously, with `timestamp_prev <= timestamp`. If there are multiple such values, it returns the value associated with the largest `timestamp_prev`. If there are no values, it returns `""`.
 
-## 题解
+**Example 1:**
 
-### 思路1
-> ...
-Time Based Key-Value Store
-```go
 ```
-
+Input
+["TimeMap", "set", "get", "get", "set", "get", "get"]
+[[], ["foo", "bar", 1], ["foo", 1], ["foo", 3], ["foo", "bar2", 4], ["foo", 4], ["foo", 5]]
+Output
+[null, null, "bar", "bar", null, "bar2", "bar2"]
+
+Explanation
+TimeMap timeMap = new TimeMap();
+timeMap.set("foo", "bar", 1);  // store the key "foo" and value "bar" along with timestamp = 1.
+timeMap.get("foo", 1);         // return "bar"
+timeMap.get("foo", 3);         // return "bar", since there is no value corresponding to foo at timestamp 3 and timestamp 2, then the only value is at timestamp 1 is "bar".
+timeMap.set("foo", "bar2", 4); // store the key "foo" and value "bar2" along with timestamp = 4.
+timeMap.get("foo", 4);         // return "bar2"
+timeMap.get("foo", 5);         // return "bar2"
+```
 
 ## 结语
 

leetcode/901-1000/0981.Time-Based-Key-Value-Store/Solution.go

@@ -1,5 +1,56 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+import "sort"
+
+type storeItem struct {
+	timestamp int
+	val       string
+}
+type TimeMap struct {
+	data map[string][]storeItem
+}
+
+func Constructor981() TimeMap {
+	return TimeMap{
+		data: make(map[string][]storeItem),
+	}
+}
+
+func (this *TimeMap) Set(key string, value string, timestamp int) {
+	if _, ok := this.data[key]; !ok {
+		this.data[key] = make([]storeItem, 0)
+	}
+	this.data[key] = append(this.data[key], storeItem{timestamp, value})
+}
+
+func (this *TimeMap) Get(key string, timestamp int) string {
+	v, ok := this.data[key]
+	if !ok {
+		return ""
+	}
+	idx := sort.Search(len(v), func(i int) bool {
+		return v[i].timestamp > timestamp
+	})
+	if idx == 0 {
+		return ""
+	}
+	return v[idx-1].val
+}
+
+type input struct {
+	key, value string
+	timestamp  int
+}
+
+func Solution(inputs []input) []string {
+	c := Constructor981()
+	ans := make([]string, 0)
+	for _, i := range inputs {
+		if i.value == "" {
+			ans = append(ans, c.Get(i.key, i.timestamp))
+			continue
+		}
+		c.Set(i.key, i.value, i.timestamp)
+	}
+	return ans
 }

leetcode/901-1000/0981.Time-Based-Key-Value-Store/Solution_test.go

@@ -10,12 +10,10 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		inputs []input
+		expect []string
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", []input{{"foo", "bar", 1}, {"foo", "", 1}, {"foo", "", 3}, {"foo", "bar2", 4}, {"foo", "", 4}, {"foo", "", 5}}, []string{"bar", "bar", "bar2", "bar2"}},
 	}
 
 	//	开始测试
@@ -30,10 +28,10 @@ func TestSolution(t *testing.T) {
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }