Merge pull request #525 from 0xff-dev/1146

Add solution and test-cases for problem 1146

leetcode/1101-1200/1146.Snapshot-Array/README.md

@@ -1,28 +1,29 @@
 # [1146.Snapshot Array][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
+Implement a SnapshotArray that supports the following interface:
 
-**Example 1:**
+- `SnapshotArray(int length)` initializes an array-like data structure with the given length. **Initially, each element equals 0**.
 
-```
-Input: a = "11", b = "1"
-Output: "100"
-```
+- `void set(index, val)` sets the element at the given `index` to be equal to `val`.
 
-## 题意
-> ...
+- `int snap()` takes a snapshot of the array and returns the `snap_id`: the total number of times we called `snap()` minus `1`.
 
-## 题解
+- `int get(index, snap_id)` returns the value at the given `index`, at the time we took the snapshot with the given `snap_id`
 
-### 思路1
-> ...
-Snapshot Array
-```go
-```
+**Example 1:**
 
+```
+Input: ["SnapshotArray","set","snap","set","get"]
+[[3],[0,5],[],[0,6],[0,0]]
+Output: [null,null,0,null,5]
+Explanation: 
+SnapshotArray snapshotArr = new SnapshotArray(3); // set the length to be 3
+snapshotArr.set(0,5);  // Set array[0] = 5
+snapshotArr.snap();  // Take a snapshot, return snap_id = 0
+snapshotArr.set(0,6);
+snapshotArr.get(0,0);  // Get the value of array[0] with snap_id = 0, return 5
+```
 
 ## 结语
 

leetcode/1101-1200/1146.Snapshot-Array/Solution.go

@@ -1,5 +1,65 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+type idWithVal struct {
+	id, val int
+}
+type SnapshotArray struct {
+	snpaId int
+	data   [][]idWithVal
+}
+
+func Constructor(length int) SnapshotArray {
+	data := make([][]idWithVal, length)
+	for i := 0; i < length; i++ {
+		data[i] = []idWithVal{{0, 0}}
+	}
+	return SnapshotArray{snpaId: 0, data: data}
+}
+
+func (this *SnapshotArray) Set(index int, val int) {
+	length := len(this.data[index])
+	if this.data[index][length-1].id != this.snpaId {
+		this.data[index] = append(this.data[index], idWithVal{id: this.snpaId, val: val})
+		return
+	}
+	this.data[index][length-1].val = val
+}
+
+func (this *SnapshotArray) Snap() int {
+	id := this.snpaId
+	this.snpaId++
+	return id
+}
+
+func (this *SnapshotArray) Get(index int, snap_id int) int {
+	// 该用二分
+	length := len(this.data[index])
+	for i := length - 1; i >= 0; i-- {
+		if this.data[index][i].id <= snap_id {
+			return this.data[index][i].val
+		}
+	}
+	return 0
+}
+
+type op struct {
+	name           string
+	index, val, id int
+}
+
+func Solution(length int, ops []op) []int {
+	c := Constructor(length)
+	ans := make([]int, 0)
+	for _, _op := range ops {
+		if _op.name == "set" {
+			c.Set(_op.index, _op.val)
+			continue
+		}
+		if _op.name == "snap" {
+			ans = append(ans, c.Snap())
+			continue
+		}
+		ans = append(ans, c.Get(_op.index, _op.id))
+	}
+	return ans
 }

leetcode/1101-1200/1146.Snapshot-Array/Solution_test.go

@@ -10,30 +10,29 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		length int
+		ops    []op
+		expect []int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", 3, []op{{name: "set", index: 0, val: 5}, {name: "snap"}, {name: "set", index: 0, val: 6}, {name: "get", index: 0, id: 0}}, []int{0, 5}},
 	}
 
 	//	开始测试
 	for i, c := range cases {
 		t.Run(c.name+" "+strconv.Itoa(i), func(t *testing.T) {
-			got := Solution(c.inputs)
+			got := Solution(c.length, c.ops)
 			if !reflect.DeepEqual(got, c.expect) {
-				t.Fatalf("expected: %v, but got: %v, with inputs: %v",
-					c.expect, got, c.inputs)
+				t.Fatalf("expected: %v, but got: %v, with inputs: %v %v",
+					c.expect, got, c.length, c.ops)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }