add new solutions

solutions/35/q3510/solution.go

@@ -0,0 +1,118 @@
+package q3510
+
+import "container/heap"
+
+type Node struct {
+	val             int
+	prev, next      *Node
+	arrPos, heapPos int
+}
+
+type MinAdjSum []*Node
+
+func (m *MinAdjSum) Len() int { return len(*m) }
+
+func (m *MinAdjSum) Less(i int, j int) bool {
+	if (*m)[i].next == nil {
+		return false
+	}
+	if (*m)[j].next == nil {
+		return true
+	}
+	s1, p1 := (*m)[i].val+(*m)[i].next.val, (*m)[i].arrPos
+	s2, p2 := (*m)[j].val+(*m)[j].next.val, (*m)[j].arrPos
+	if s1 == s2 {
+		return p1 < p2
+	}
+	return s1 < s2
+}
+
+func (m *MinAdjSum) Push(x any) {
+	elem := x.(*Node)
+	elem.heapPos = len(*m)
+	*m = append(*m, elem)
+}
+
+func (m *MinAdjSum) Pop() any {
+	ret := (*m)[len(*m)-1]
+	(*m) = (*m)[:len(*m)-1]
+	return ret
+}
+
+func (m *MinAdjSum) Swap(i int, j int) {
+	(*m)[i].heapPos = j
+	(*m)[j].heapPos = i
+	(*m)[i], (*m)[j] = (*m)[j], (*m)[i]
+}
+
+func minimumPairRemoval(nums []int) int {
+	outOfOrder := 0
+	for i := range len(nums) - 1 {
+		if nums[i] > nums[i+1] {
+			outOfOrder++
+		}
+	}
+	if outOfOrder == 0 {
+		return 0
+	}
+
+	nodes := make([]Node, len(nums))
+	hp := make(MinAdjSum, len(nums))
+	for i := range nums {
+		nodes[i] = Node{val: nums[i], heapPos: i, arrPos: i}
+		hp[i] = &nodes[i]
+
+		if i > 0 {
+			nodes[i].prev = &nodes[i-1]
+		}
+		if i+1 < len(nums) {
+			nodes[i].next = &nodes[i+1]
+		}
+	}
+	heap.Init(&hp)
+
+	ops := 0
+	for ; outOfOrder > 0; ops++ {
+		node := hp[0]
+		next, prev := node.next, node.prev
+
+		heap.Remove(&hp, node.heapPos)
+		heap.Remove(&hp, next.heapPos)
+		if prev != nil {
+			heap.Remove(&hp, prev.heapPos)
+		}
+
+		// Update outOfOrder
+		if next.val < node.val {
+			outOfOrder--
+		}
+		if next.next != nil && next.next.val < next.val {
+			outOfOrder--
+		}
+		if prev != nil && node.val < prev.val {
+			outOfOrder--
+		}
+
+		node.val += next.val
+		if prev != nil && node.val < prev.val {
+			outOfOrder++
+		}
+		if next.next != nil && next.next.val < node.val {
+			outOfOrder++
+		}
+
+		// Update links & fix heap
+		node.next = next.next
+		if next.next != nil {
+			next.next.prev = node
+		}
+
+		heap.Push(&hp, node)
+		if prev != nil {
+			heap.Push(&hp, prev)
+		}
+	}
+	return ops
+}
+
+var _ = minimumPairRemoval