add new solutions

solutions/0/q23/solution.go

@@ -0,0 +1,52 @@
+package q23
+
+import "container/heap"
+
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+type MinNodeHp []*ListNode
+
+func (m *MinNodeHp) Len() int               { return len(*m) }
+func (m *MinNodeHp) Less(i int, j int) bool { return (*m)[i].Val < (*m)[j].Val }
+func (m *MinNodeHp) Push(x any)             { *m = append(*m, x.(*ListNode)) }
+func (m *MinNodeHp) Swap(i int, j int)      { (*m)[i], (*m)[j] = (*m)[j], (*m)[i] }
+
+func (m *MinNodeHp) Pop() any {
+	*m = (*m)[:len(*m)-1]
+	return nil
+}
+
+var _ heap.Interface = &MinNodeHp{}
+
+func mergeKLists(lists []*ListNode) *ListNode {
+	hp := make(MinNodeHp, 0, len(lists))
+	for i := range lists {
+		if lists[i] != nil {
+			hp = append(hp, lists[i])
+		}
+	}
+	heap.Init(&hp)
+
+	head := &ListNode{}
+	tail := head
+
+	for len(hp) > 0 {
+		tail.Next = hp[0]
+		tail = tail.Next
+
+		hp[0] = hp[0].Next
+		if hp[0] == nil {
+			heap.Remove(&hp, 0)
+		} else {
+			heap.Fix(&hp, 0)
+		}
+	}
+
+	tail.Next = nil
+	return head.Next
+}
+
+var _ = mergeKLists

solutions/0/q62/solution.go

@@ -0,0 +1,15 @@
+package q62
+
+func uniquePaths(m int, n int) int {
+	buf := make([]int, n)
+	buf[0] = 1
+
+	for range m {
+		for c := 1; c < n; c++ {
+			buf[c] += buf[c-1]
+		}
+	}
+	return buf[n-1]
+}
+
+var _ = uniquePaths

solutions/0/q94/solution.go

@@ -0,0 +1,25 @@
+package q94
+
+type TreeNode struct {
+	Val   int
+	Left  *TreeNode
+	Right *TreeNode
+}
+
+func traversal(node *TreeNode, ret *[]int) {
+	if node == nil {
+		return
+	}
+	traversal(node.Left, ret)
+	*ret = append(*ret, node.Val)
+	traversal(node.Right, ret)
+}
+
+func inorderTraversal(root *TreeNode) []int {
+	// left, center, right
+	ret := []int{}
+	traversal(root, &ret)
+	return ret
+}
+
+var _ = inorderTraversal