Merge pull request #643 from 0xff-dev/284

Add solution and test-cases for problem 284

leetcode/201-300/0284.Peeking-Iterator/README.md

@@ -1,28 +1,34 @@
 # [284.Peeking Iterator][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 an iterator that supports the `peek` operation on an existing iterator in addition to the `hasNext` and the `next` operations.
 
-**Example 1:**
+Implement the `PeekingIterator` class:
 
-```
-Input: a = "11", b = "1"
-Output: "100"
-```
+- `PeekingIterator(Iterator<int> nums)` Initializes the object with the given integer iterator `iterator`.
+- `int next()` Returns the next element in the array and moves the pointer to the next element.
+- `boolean hasNext()` Returns `true` if there are still elements in the array.
+- `int peek()` Returns the next element in the array without moving the pointer.
 
-## 题意
-> ...
+**Note**: Each language may have a different implementation of the constructor and `Iterator`, but they all support the `int next()` and `boolean hasNext()` functions.
 
-## 题解
+**Example 1:**
 
-### 思路1
-> ...
-Peeking Iterator
-```go
 ```
-
+Input
+["PeekingIterator", "next", "peek", "next", "next", "hasNext"]
+[[[1, 2, 3]], [], [], [], [], []]
+Output
+[null, 1, 2, 2, 3, false]
+
+Explanation
+PeekingIterator peekingIterator = new PeekingIterator([1, 2, 3]); // [1,2,3]
+peekingIterator.next();    // return 1, the pointer moves to the next element [1,2,3].
+peekingIterator.peek();    // return 2, the pointer does not move [1,2,3].
+peekingIterator.next();    // return 2, the pointer moves to the next element [1,2,3]
+peekingIterator.next();    // return 3, the pointer moves to the next element [1,2,3]
+peekingIterator.hasNext(); // return False
+```
 
 ## 结语
 

leetcode/201-300/0284.Peeking-Iterator/Solution.go

@@ -1,5 +1,64 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+type Iterator struct {
+	data []int
+	idx  int
+}
+
+func (this *Iterator) hasNext() bool {
+	return this.idx < len(this.data)-1
+}
+func (this *Iterator) next() int {
+	ans := this.data[this.idx]
+	this.idx++
+	return ans
+}
+
+type PeekingIterator struct {
+	iter  *Iterator
+	peekV int
+}
+
+func Constructor284(iter *Iterator) *PeekingIterator {
+	return &PeekingIterator{iter: iter, peekV: -1}
+}
+
+func (this *PeekingIterator) hasNext() bool {
+	if !this.iter.hasNext() {
+		return this.peekV != -1
+	}
+	return this.iter.hasNext()
+}
+
+func (this *PeekingIterator) next() int {
+	if this.peekV != -1 {
+		ans := this.peekV
+		this.peekV = -1
+		return ans
+	}
+	return this.iter.next()
+}
+
+func (this *PeekingIterator) peek() int {
+	if this.peekV == -1 {
+		this.peekV = this.iter.next()
+	}
+	return this.peekV
+}
+
+func Solution(iter *Iterator, options []string) []interface{} {
+    ans := make([]interface{}, 0)
+    o := Constructor284(iter)
+    for _, op := range options {
+        if op == "next" {
+            ans = append(ans, o.next())
+            continue
+        }
+        if op == "peek" {
+            ans = append(ans, o.peek())
+            continue
+        }
+        ans = append(ans, o.hasNext())
+    }
+    return ans
 }

leetcode/201-300/0284.Peeking-Iterator/Solution_test.go

@@ -9,19 +9,18 @@ import (
 func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
-		name   string
-		inputs bool
-		expect bool
+		name       string
+		inputs     *Iterator
+		operations []string
+		expect     []interface{}
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", &Iterator{data: []int{1, 2, 3}}, []string{"next", "peek", "next", "next", "hasNext"}, []interface{}{1, 2, 2, 3, false}},
 	}
 
 	//	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.inputs, c.operations)
 			if !reflect.DeepEqual(got, c.expect) {
 				t.Fatalf("expected: %v, but got: %v, with inputs: %v",
 					c.expect, got, c.inputs)
@@ -30,10 +29,10 @@ 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() {
 }