From 71ac4f11a820b333c3d93441d613ee73915fcb62 Mon Sep 17 00:00:00 2001
From: Rostislav Kuratch <kr0st@bioreactor.me>
Date: Wed, 16 Feb 2022 21:05:55 +0200
Subject: [PATCH] "Shortest Subarray with Sum at Least K" hard task No 862
 solution using 2 queues, still failing by time complexity

---
 862-shortest-subarray-with-sum-at-least-k.go | 99 ++++++++++++++------
 1 file changed, 68 insertions(+), 31 deletions(-)

diff --git a/862-shortest-subarray-with-sum-at-least-k.go b/862-shortest-subarray-with-sum-at-least-k.go
index fa8d401..99ac8d0 100644
--- a/862-shortest-subarray-with-sum-at-least-k.go
+++ b/862-shortest-subarray-with-sum-at-least-k.go
@@ -1,44 +1,81 @@
 package main
 
+import "fmt"
+
+type Queue struct {
+	front  int
+	rear   int
+	size   int
+	QArray [100000]int
+}
+
+func (q *Queue) initQueue(size int) {
+	q.size = size
+	//q.QArray = [size]int{}
+	q.front = -1
+	q.rear = -1
+}
+
+func (q *Queue) enqueue(value int) {
+	if q.rear == q.size-1 {
+		fmt.Println("Queue is Full")
+		return
+	} else {
+		q.rear++
+		q.QArray[q.rear] = value
+	}
+}
+
+func (q *Queue) dequeue() int {
+	var x int = -1
+	if q.front == q.rear {
+		fmt.Println("Queue is Empty!")
+	} else {
+		q.front++
+		x = q.QArray[q.front]
+	}
+	return x
+}
+
+func (q *Queue) erase() {
+	q.front = -1
+	q.rear = -1
+}
+
 func ShortestSubarray(nums []int, k int) int {
 	if len(nums) == 0 {
 		return -1
 	}
 
-	sz := 999999
-	sum := nums[0]
-	carry := 1
+	queue := &Queue{}
+	queue2 := &Queue{}
 
-	for i := 0; i < len(nums)-1; i++ {
-		if sum >= k {
-			if (carry > 0) && (sz > carry) {
-				sz = carry
-			}
-		}
-		sum = nums[i]
-		for j := i + 1; j < len(nums); j++ {
-			if sum >= k {
-				if sz > (j - i) {
-					sz = j - i
-				}
-				break
-			} else {
-				sum += nums[j]
-				carry = j - i + 1
+	queue.initQueue(100000)
+	queue2.initQueue(100000)
+
+	for i, n := range nums {
+		if i < len(nums) {
+			queue.enqueue(n)
+		}
+		if n >= k {
+			return 1
+		}
+	}
+
+	for wndSz := 2; wndSz <= len(nums); wndSz++ {
+		for i := wndSz - 1; i < len(nums); i++ {
+			el := queue.dequeue()
+			s := el + nums[i]
+			queue2.enqueue(s)
+			if s >= k {
+				return wndSz
 			}
 		}
+		t := queue
+		queue = queue2
+		queue2 = t
+		queue2.erase()
 	}
 
-	if sz == 999999 {
-		if sum >= k {
-			return carry
-		}
-		return -1
-	}
-
-	if (sum >= k) && (carry > 0) && (carry < sz) {
-		return carry
-	}
-
-	return sz
+	return -1
 }