"Shortest Subarray with Sum at Least K" hard task No 862 queue version improvement

862-shortest-subarray-with-sum-at-least-k.go

@@ -1,74 +1,58 @@
 package main
 
-type Queue struct {
-	front int
-	rear  int
-	size  int
-	queue [100000]int
-}
-
-func (q *Queue) initQueue(size int) {
-	q.size = size
-	q.front = -1
-	q.rear = -1
-}
-
-func (q *Queue) enqueue(value int) {
-	if q.rear == q.size-1 {
-		return
-	} else {
-		q.rear++
-		q.queue[q.rear] = value
-	}
-}
-
-func (q *Queue) dequeue() int {
-	var x int = -1
-	if q.front != q.rear {
-		q.front++
-		x = q.queue[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
 	}
 
-	queue := &Queue{}
-	queue2 := &Queue{}
+	queue := [100000]int{}
+	queue2 := [100000]int{}
 
-	queue.initQueue(100000)
-	queue2.initQueue(100000)
+	qIterator := &queue
+	q2Iterator := &queue2
+
+	t := qIterator
+
+	qEndPtr := -1
+	qBeginPtr := -1
+
+	q2EndPtr := -1
+	q2BeginPtr := -1
+
+	lenNums := len(nums)
 
 	for i, n := range nums {
-		if i < len(nums) {
-			queue.enqueue(n)
+		if i < lenNums {
+			qEndPtr++
+			qIterator[qEndPtr] = 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 {
+	wndSz := 0
+	i := 0
+
+	for wndSz = 2; wndSz <= lenNums; wndSz++ {
+		for i = wndSz - 1; i < lenNums; i++ {
+			qBeginPtr++
+			q2EndPtr++
+			q2Iterator[q2EndPtr] = qIterator[qBeginPtr] + nums[i]
+			if q2Iterator[q2EndPtr] >= k {
 				return wndSz
 			}
 		}
-		t := queue
-		queue = queue2
-		queue2 = t
-		queue2.erase()
+
+		t = qIterator
+		qIterator = q2Iterator
+		q2Iterator = t
+
+		qBeginPtr = q2BeginPtr
+		qEndPtr = q2EndPtr
+
+		q2BeginPtr = -1
+		q2EndPtr = -1
 	}
 
 	return -1