update

superj80820 · May 16, 2024 · 90cb9a9 · 90cb9a9
1 parent 114a116
commit 90cb9a9
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Showing 10 changed files with 37 additions and 22 deletions.
diff --git a/neetcode/0021-merge-two-sorted-lists.go b/neetcode/0021-merge-two-sorted-lists.go
@@ -1,4 +1,4 @@
-// tags: linked-list, star3, easy, practice-count:2
+// tags: linked-list, star3, easy, practice-count:3
 
 /**
  * Definition for singly-linked list.
@@ -11,12 +11,6 @@
 // space complexity: O(1)
 // `n` is length of all node
 func mergeTwoLists(list1 *ListNode, list2 *ListNode) *ListNode {
-	if list1 == nil {
-		return list2
-	} else if list2 == nil {
-		return list1
-	}
-
 	dummy := new(ListNode)
 
 	cur := dummy
@@ -38,4 +32,21 @@ func mergeTwoLists(list1 *ListNode, list2 *ListNode) *ListNode {
 	}
 
 	return dummy.Next
+}
+
+// time complexity: O(n)
+// space complexity: O(n)
+// `n` is length of all node
+func mergeTwoLists(list1 *ListNode, list2 *ListNode) *ListNode {
+	if list1 == nil {
+		return list2
+	} else if list2 == nil {
+		return list1
+	}
+	if list1.Val <= list2.Val {
+		list1.Next = mergeTwoLists(list1.Next, list2)
+		return list1
+	}
+	list2.Next = mergeTwoLists(list2.Next, list1)
+	return list2
 }
diff --git a/neetcode/0042-trapping-rain-water.go b/neetcode/0042-trapping-rain-water.go
@@ -1,4 +1,4 @@
-// tags: two-pointers, star3, hard, practice-count:2
+// tags: two-pointers, star3, hard, practice-count:3
 
 // time complexity: O(n)
 // space complexity: O(1)

diff --git a/neetcode/0070-climbing-stairs.go b/neetcode/0070-climbing-stairs.go
@@ -1,15 +1,19 @@
-// tags: 1d-dp, star3, easy, practice-count:2
+// tags: 1d-dp, star3, easy, practice-count:3
 
 // time complexity: O(n)
 // space complexity: O(1)
 func climbStairs(n int) int {
-	n1, n2, n3 := 0, 0, 1
-	for i := 0; i < n; i++ {
-		n1 = n2
-		n2 = n3
-		n3 = n2 + n1
+	if n == 1 {
+		return 1
 	}
-	return n3
+	n1, n2 := 1, 2
+	for i := 2; i < n; i++ {
+		temp := n2
+		n2 = n1 + n2
+		n1 = temp
+	}
+
+	return n2
 }
 
 // [8,5,3,2,1,1]

diff --git a/neetcode/0100-same-tree.go b/neetcode/0100-same-tree.go
@@ -1,4 +1,4 @@
-// tags: trees, star1, easy, practice-count:2
+// tags: trees, star1, easy, practice-count:3
 
 /**
  * Definition for a binary tree node.

diff --git a/neetcode/0141-linked-list-cycle.go b/neetcode/0141-linked-list-cycle.go
@@ -1,4 +1,4 @@
-// tags: linked-list, star3, todo(write), easy, practice-count:2
+// tags: linked-list, star3, todo(write), easy, practice-count:3
 
 /**
  * Definition for singly-linked list.

diff --git a/neetcode/0206-reverse-linked-list.go b/neetcode/0206-reverse-linked-list.go
@@ -1,4 +1,4 @@
-// tags: linked-list, star1, easy, practice-count:2
+// tags: linked-list, star1, easy, practice-count:3
 
 package neetcode
 

diff --git a/neetcode/0208-implement-trie-prefix-tree.go b/neetcode/0208-implement-trie-prefix-tree.go
@@ -1,4 +1,4 @@
-// tags: tries, medium, practice-count:2
+// tags: tries, medium, practice-count:3
 
 type Trie struct {
 	Child [26]*Trie

diff --git a/neetcode/0322-coin-change.go b/neetcode/0322-coin-change.go
@@ -1,4 +1,4 @@
-// tags: 1d-dp, star3, medium, practice-count:3
+// tags: 1d-dp, star3, medium, practice-count:4
 
 import "math"
 

diff --git a/neetcode/0518-coin-change-ii.go b/neetcode/0518-coin-change-ii.go
@@ -1,4 +1,4 @@
-// tags: 2d-dp, star3, dfs, medium, practice-count:3
+// tags: 2d-dp, star3, dfs, medium, practice-count:4
 
 // time complexity: O(m*n)
 // space complexity: O(m*n)

diff --git a/neetcode/0704-binary-search.go b/neetcode/0704-binary-search.go
@@ -1,4 +1,4 @@
-// tags: binary-search, star3, easy, practice-count:2
+// tags: binary-search, star3, easy, practice-count:3
 
 // time complexity: O(logn)
 // space complexity: O(1)