Merge pull request #1035 from 0xff-dev/862

Add solution and test-cases for problem 862

Author: 6boris

leetcode/801-900/0862.Shortest-Subarray-with-Sum-at-Least-K/README.md

@@ -1,28 +1,30 @@
 # [862.Shortest Subarray with Sum at Least K][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
+Given an integer array `nums` and an integer `k`, return the length of the shortest non-empty **subarray** of `nums` with a sum of at least `k`. If there is no such **subarray**, return `-1`.
+
+A **subarray** is a **contiguous** part of an array.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: nums = [1], k = 1
+Output: 1
 ```
 
-## 题意
-> ...
+**Example 2:**
 
-## 题解
-
-### 思路1
-> ...
-Shortest Subarray with Sum at Least K
-```go
+```
+Input: nums = [1,2], k = 4
+Output: -1
 ```
 
+**Example 3:**
+
+```
+Input: nums = [2,-1,2], k = 3
+Output: 3
+```
 
 ## 结语
 

leetcode/801-900/0862.Shortest-Subarray-with-Sum-at-Least-K/Solution.go

@@ -1,5 +1,80 @@
 package Solution
 
-func Solution(x bool) bool {
+import (
+	"container/heap"
+	"container/list"
+	"math"
+)
+
+func Solution(nums []int, k int) int {
+	n := len(nums)
+	prefixSum := make([]int, n+1)
+	for i := 0; i < n; i++ {
+		prefixSum[i+1] = prefixSum[i] + nums[i]
+	}
+
+	minLength := math.MaxInt32
+	deque := list.New()
+
+	for i := 0; i <= n; i++ {
+		for deque.Len() > 0 && prefixSum[i]-prefixSum[deque.Front().Value.(int)] >= k {
+			minLength = min(minLength, i-deque.Remove(deque.Front()).(int))
+		}
+
+		for deque.Len() > 0 && prefixSum[i] <= prefixSum[deque.Back().Value.(int)] {
+			deque.Remove(deque.Back())
+		}
+
+		deque.PushBack(i)
+	}
+
+	if minLength == math.MaxInt32 {
+		return -1
+	}
+	return minLength
+}
+
+type heap862 struct {
+	v, i int
+}
+type heap862list []heap862
+
+func (h *heap862list) Len() int {
+	return len(*h)
+}
+func (h *heap862list) Swap(i, j int) {
+	(*h)[i], (*h)[j] = (*h)[j], (*h)[i]
+}
+
+func (h *heap862list) Less(i, j int) bool {
+	return (*h)[i].v < (*h)[j].v
+}
+func (h *heap862list) Push(x any) {
+	*h = append(*h, x.(heap862))
+}
+func (h *heap862list) Pop() any {
+	old := *h
+	l := len(old)
+	x := old[l-1]
+	*h = old[:l-1]
 	return x
 }
+
+func Solution1(nums []int, k int) int {
+	h := heap862list{{0, -1}}
+	cur := 0
+	l := len(nums)
+	ans := -1
+	i := 0
+	for ; i < l; i++ {
+		cur += nums[i]
+		for len(h) > 0 && cur-h[0].v >= k {
+			top := heap.Pop(&h).(heap862)
+			if ans == -1 || ans > i-top.i {
+				ans = i - top.i
+			}
+		}
+		heap.Push(&h, heap862{cur, i})
+	}
+	return ans
+}

leetcode/801-900/0862.Shortest-Subarray-with-Sum-at-Least-K/Solution_test.go

@@ -10,30 +10,56 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		nums   []int
+		k      int
+		expect int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", []int{1}, 1, 1},
+		{"TestCase2", []int{1, 2}, 4, -1},
+		{"TestCase3", []int{2, -1, 2}, 3, 3},
 	}
 
 	//	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.nums, c.k)
 			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.nums, c.k)
 			}
 		})
 	}
 }
 
-//	压力测试
+func TestSolution1(t *testing.T) {
+	//	测试用例
+	cases := []struct {
+		name   string
+		nums   []int
+		k      int
+		expect int
+	}{
+		{"TestCase1", []int{1}, 1, 1},
+		{"TestCase2", []int{1, 2}, 4, -1},
+		{"TestCase3", []int{2, -1, 2}, 3, 3},
+	}
+
+	//	开始测试
+	for i, c := range cases {
+		t.Run(c.name+" "+strconv.Itoa(i), func(t *testing.T) {
+			got := Solution1(c.nums, c.k)
+			if !reflect.DeepEqual(got, c.expect) {
+				t.Fatalf("expected: %v, but got: %v, with inputs: %v %v",
+					c.expect, got, c.nums, c.k)
+			}
+		})
+	}
+}
+
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }