feat: update solutions to lcci problem: No.02.05 (doocs#2322)

yanglbme · web-flow · commit edc2ea88479a · 2024-02-06T19:48:02.000+08:00
No.02.05.Sum Lists
diff --git a/lcci/02.05.Sum Lists/README.md b/lcci/02.05.Sum Lists/README.md
@@ -29,7 +29,15 @@
 
 ## 解法
 
-### 方法一
+### 方法一：模拟
+
+我们同时遍历两个链表 $l_1$ 和 $l_2$，并使用变量 $carry$ 表示当前是否有进位。
+
+每次遍历时，我们取出对应链表的当前位，计算它们与进位 $carry$ 的和，然后更新进位的值，最后将当前位的值加入答案链表。如果两个链表都遍历完了，并且进位为 $0$ 时，遍历结束。
+
+最后我们返回答案链表的头节点即可。
+
+时间复杂度 $O(\max(m, n))$，其中 $m$ 和 $n$ 分别为两个链表的长度。我们需要遍历两个链表的全部位置，而处理每个位置只需要 $O(1)$ 的时间。忽略答案的空间消耗，空间复杂度 $O(1)$。
 
 <!-- tabs:start -->
 
@@ -43,15 +51,15 @@
 
 class Solution:
     def addTwoNumbers(self, l1: ListNode, l2: ListNode) -> ListNode:
-        dummy = cur = ListNode(0)
-        carry = 0
+        dummy = ListNode()
+        carry, curr = 0, dummy
         while l1 or l2 or carry:
-            carry += (0 if not l1 else l1.val) + (0 if not l2 else l2.val)
-            cur.next = ListNode(carry % 10)
-            cur = cur.next
-            carry //= 10
-            l1 = None if not l1 else l1.next
-            l2 = None if not l2 else l2.next
+            s = (l1.val if l1 else 0) + (l2.val if l2 else 0) + carry
+            carry, val = divmod(s, 10)
+            curr.next = ListNode(val)
+            curr = curr.next
+            l1 = l1.next if l1 else None
+            l2 = l2.next if l2 else None
         return dummy.next
 ```
 
@@ -66,8 +74,8 @@ class Solution:
  */
 class Solution {
     public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
+        ListNode dummy = new ListNode(0);
         int carry = 0;
-        ListNode dummy = new ListNode(-1);
         ListNode cur = dummy;
         while (l1 != null || l2 != null || carry != 0) {
             int s = (l1 == null ? 0 : l1.val) + (l2 == null ? 0 : l2.val) + carry;
diff --git a/lcci/02.05.Sum Lists/README_EN.md b/lcci/02.05.Sum Lists/README_EN.md
@@ -32,7 +32,15 @@
 
 ## Solutions
 
-### Solution 1
+### Solution 1: Simulation
+
+We traverse two linked lists $l_1$ and $l_2$ simultaneously, and use a variable $carry$ to indicate whether there is a carry-over currently.
+
+During each traversal, we take out the current digit of the corresponding linked list, calculate the sum of them and the carry-over $carry$, then update the value of the carry-over, and finally add the value of the current digit to the answer linked list. The traversal ends when both linked lists have been traversed and the carry-over is $0$.
+
+Finally, we return the head node of the answer linked list.
+
+The time complexity is $O(\max(m, n))$, where $m$ and $n$ are the lengths of the two linked lists respectively. We need to traverse all positions of the two linked lists, and it only takes $O(1)$ time to process each position. Ignoring the space consumption of the answer, the space complexity is $O(1)$.
 
 <!-- tabs:start -->
 
@@ -46,15 +54,15 @@
 
 class Solution:
     def addTwoNumbers(self, l1: ListNode, l2: ListNode) -> ListNode:
-        dummy = cur = ListNode(0)
-        carry = 0
+        dummy = ListNode()
+        carry, curr = 0, dummy
         while l1 or l2 or carry:
-            carry += (0 if not l1 else l1.val) + (0 if not l2 else l2.val)
-            cur.next = ListNode(carry % 10)
-            cur = cur.next
-            carry //= 10
-            l1 = None if not l1 else l1.next
-            l2 = None if not l2 else l2.next
+            s = (l1.val if l1 else 0) + (l2.val if l2 else 0) + carry
+            carry, val = divmod(s, 10)
+            curr.next = ListNode(val)
+            curr = curr.next
+            l1 = l1.next if l1 else None
+            l2 = l2.next if l2 else None
         return dummy.next
 ```
 
@@ -69,8 +77,8 @@ class Solution:
  */
 class Solution {
     public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
+        ListNode dummy = new ListNode(0);
         int carry = 0;
-        ListNode dummy = new ListNode(-1);
         ListNode cur = dummy;
         while (l1 != null || l2 != null || carry != 0) {
             int s = (l1 == null ? 0 : l1.val) + (l2 == null ? 0 : l2.val) + carry;
diff --git a/lcci/02.05.Sum Lists/Solution.java b/lcci/02.05.Sum Lists/Solution.java
@@ -8,8 +8,8 @@
  */
 class Solution {
     public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
+        ListNode dummy = new ListNode(0);
         int carry = 0;
-        ListNode dummy = new ListNode(-1);
         ListNode cur = dummy;
         while (l1 != null || l2 != null || carry != 0) {
             int s = (l1 == null ? 0 : l1.val) + (l2 == null ? 0 : l2.val) + carry;
diff --git a/lcci/02.05.Sum Lists/Solution.py b/lcci/02.05.Sum Lists/Solution.py
@@ -7,13 +7,13 @@
 
 class Solution:
     def addTwoNumbers(self, l1: ListNode, l2: ListNode) -> ListNode:
-        dummy = cur = ListNode(0)
-        carry = 0
+        dummy = ListNode()
+        carry, curr = 0, dummy
         while l1 or l2 or carry:
-            carry += (0 if not l1 else l1.val) + (0 if not l2 else l2.val)
-            cur.next = ListNode(carry % 10)
-            cur = cur.next
-            carry //= 10
-            l1 = None if not l1 else l1.next
-            l2 = None if not l2 else l2.next
+            s = (l1.val if l1 else 0) + (l2.val if l2 else 0) + carry
+            carry, val = divmod(s, 10)
+            curr.next = ListNode(val)
+            curr = curr.next
+            l1 = l1.next if l1 else None
+            l2 = l2.next if l2 else None
         return dummy.next
diff --git a/solution/README.md b/solution/README.md
@@ -3014,7 +3014,7 @@
 |  3001  |  [捕获黑皇后需要的最少移动次数](/solution/3000-3099/3001.Minimum%20Moves%20to%20Capture%20The%20Queen/README.md)  |  `数组`,`枚举`  |  中等  |  第 379 场周赛  |
 |  3002  |  [移除后集合的最多元素数](/solution/3000-3099/3002.Maximum%20Size%20of%20a%20Set%20After%20Removals/README.md)  |  `贪心`,`数组`,`哈希表`  |  中等  |  第 379 场周赛  |
 |  3003  |  [执行操作后的最大分割数量](/solution/3000-3099/3003.Maximize%20the%20Number%20of%20Partitions%20After%20Operations/README.md)  |  `位运算`,`字符串`,`动态规划`,`状态压缩`  |  困难  |  第 379 场周赛  |
-|  3004  |  [相同颜色的最大子树](/solution/3000-3099/3004.Maximum%20Subtree%20of%20the%20Same%20Color/README.md)  |  `树`,`深度优先搜索`,`数组`  |  中等  |  🔒  |
+|  3004  |  [相同颜色的最大子树](/solution/3000-3099/3004.Maximum%20Subtree%20of%20the%20Same%20Color/README.md)  |  `树`,`深度优先搜索`,`数组`,`动态规划`  |  中等  |  🔒  |
 |  3005  |  [最大频率元素计数](/solution/3000-3099/3005.Count%20Elements%20With%20Maximum%20Frequency/README.md)  |  `数组`,`哈希表`,`计数`  |  简单  |  第 380 场周赛  |
 |  3006  |  [找出数组中的美丽下标 I](/solution/3000-3099/3006.Find%20Beautiful%20Indices%20in%20the%20Given%20Array%20I/README.md)  |  `双指针`,`字符串`,`二分查找`,`字符串匹配`,`哈希函数`,`滚动哈希`  |  中等  |  第 380 场周赛  |
 |  3007  |  [价值和小于等于 K 的最大数字](/solution/3000-3099/3007.Maximum%20Number%20That%20Sum%20of%20the%20Prices%20Is%20Less%20Than%20or%20Equal%20to%20K/README.md)  |  `位运算`,`二分查找`,`动态规划`  |  中等  |  第 380 场周赛  |
@@ -3033,15 +3033,15 @@
 |  3020  |  [子集中元素的最大数量](/solution/3000-3099/3020.Find%20the%20Maximum%20Number%20of%20Elements%20in%20Subset/README.md)  |  `数组`,`哈希表`,`枚举`  |  中等  |  第 382 场周赛  |
 |  3021  |  [Alice 和 Bob 玩鲜花游戏](/solution/3000-3099/3021.Alice%20and%20Bob%20Playing%20Flower%20Game/README.md)  |  `数学`  |  中等  |  第 382 场周赛  |
 |  3022  |  [给定操作次数内使剩余元素的或值最小](/solution/3000-3099/3022.Minimize%20OR%20of%20Remaining%20Elements%20Using%20Operations/README.md)  |  `贪心`,`位运算`,`数组`  |  困难  |  第 382 场周赛  |
-|  3023  |  [在无限流中寻找模式 I](/solution/3000-3099/3023.Find%20Pattern%20in%20Infinite%20Stream%20I/README.md)  |    |  中等  |  🔒  |
-|  3024  |  [三角形类型 II](/solution/3000-3099/3024.Type%20of%20Triangle%20II/README.md)  |    |  简单  |  第 123 场双周赛  |
-|  3025  |  [人员站位的方案数 I](/solution/3000-3099/3025.Find%20the%20Number%20of%20Ways%20to%20Place%20People%20I/README.md)  |    |  中等  |  第 123 场双周赛  |
-|  3026  |  [最大好子数组和](/solution/3000-3099/3026.Maximum%20Good%20Subarray%20Sum/README.md)  |    |  中等  |  第 123 场双周赛  |
-|  3027  |  [人员站位的方案数 II](/solution/3000-3099/3027.Find%20the%20Number%20of%20Ways%20to%20Place%20People%20II/README.md)  |    |  困难  |  第 123 场双周赛  |
-|  3028  |  [边界上的蚂蚁](/solution/3000-3099/3028.Ant%20on%20the%20Boundary/README.md)  |    |  简单  |  第 383 场周赛  |
-|  3029  |  [将单词恢复初始状态所需的最短时间 I](/solution/3000-3099/3029.Minimum%20Time%20to%20Revert%20Word%20to%20Initial%20State%20I/README.md)  |    |  中等  |  第 383 场周赛  |
-|  3030  |  [找出网格的区域平均强度](/solution/3000-3099/3030.Find%20the%20Grid%20of%20Region%20Average/README.md)  |    |  中等  |  第 383 场周赛  |
-|  3031  |  [将单词恢复初始状态所需的最短时间 II](/solution/3000-3099/3031.Minimum%20Time%20to%20Revert%20Word%20to%20Initial%20State%20II/README.md)  |    |  困难  |  第 383 场周赛  |
+|  3023  |  [在无限流中寻找模式 I](/solution/3000-3099/3023.Find%20Pattern%20in%20Infinite%20Stream%20I/README.md)  |  `数组`,`字符串`,`字符串匹配`,`滑动窗口`  |  中等  |  🔒  |
+|  3024  |  [三角形类型 II](/solution/3000-3099/3024.Type%20of%20Triangle%20II/README.md)  |  `数组`,`数学`,`排序`  |  简单  |  第 123 场双周赛  |
+|  3025  |  [人员站位的方案数 I](/solution/3000-3099/3025.Find%20the%20Number%20of%20Ways%20to%20Place%20People%20I/README.md)  |  `几何`,`数组`,`数学`,`枚举`,`排序`  |  中等  |  第 123 场双周赛  |
+|  3026  |  [最大好子数组和](/solution/3000-3099/3026.Maximum%20Good%20Subarray%20Sum/README.md)  |  `数组`,`哈希表`,`前缀和`  |  中等  |  第 123 场双周赛  |
+|  3027  |  [人员站位的方案数 II](/solution/3000-3099/3027.Find%20the%20Number%20of%20Ways%20to%20Place%20People%20II/README.md)  |  `几何`,`数组`,`数学`,`枚举`,`排序`  |  困难  |  第 123 场双周赛  |
+|  3028  |  [边界上的蚂蚁](/solution/3000-3099/3028.Ant%20on%20the%20Boundary/README.md)  |  `数组`,`前缀和`,`模拟`  |  简单  |  第 383 场周赛  |
+|  3029  |  [将单词恢复初始状态所需的最短时间 I](/solution/3000-3099/3029.Minimum%20Time%20to%20Revert%20Word%20to%20Initial%20State%20I/README.md)  |  `字符串`,`字符串匹配`,`哈希函数`,`滚动哈希`  |  中等  |  第 383 场周赛  |
+|  3030  |  [找出网格的区域平均强度](/solution/3000-3099/3030.Find%20the%20Grid%20of%20Region%20Average/README.md)  |  `数组`,`矩阵`  |  中等  |  第 383 场周赛  |
+|  3031  |  [将单词恢复初始状态所需的最短时间 II](/solution/3000-3099/3031.Minimum%20Time%20to%20Revert%20Word%20to%20Initial%20State%20II/README.md)  |  `字符串`,`字符串匹配`,`哈希函数`,`滚动哈希`  |  困难  |  第 383 场周赛  |
 
 ## 版权
 
diff --git a/solution/README_EN.md b/solution/README_EN.md
@@ -3012,7 +3012,7 @@ Press <kbd>Control</kbd> + <kbd>F</kbd>(or <kbd>Command</kbd> + <kbd>F</kbd> on
 |  3001  |  [Minimum Moves to Capture The Queen](/solution/3000-3099/3001.Minimum%20Moves%20to%20Capture%20The%20Queen/README_EN.md)  |  `Array`,`Enumeration`  |  Medium  |  Weekly Contest 379  |
 |  3002  |  [Maximum Size of a Set After Removals](/solution/3000-3099/3002.Maximum%20Size%20of%20a%20Set%20After%20Removals/README_EN.md)  |  `Greedy`,`Array`,`Hash Table`  |  Medium  |  Weekly Contest 379  |
 |  3003  |  [Maximize the Number of Partitions After Operations](/solution/3000-3099/3003.Maximize%20the%20Number%20of%20Partitions%20After%20Operations/README_EN.md)  |  `Bit Manipulation`,`String`,`Dynamic Programming`,`Bitmask`  |  Hard  |  Weekly Contest 379  |
-|  3004  |  [Maximum Subtree of the Same Color](/solution/3000-3099/3004.Maximum%20Subtree%20of%20the%20Same%20Color/README_EN.md)  |  `Tree`,`Depth-First Search`,`Array`  |  Medium  |  🔒  |
+|  3004  |  [Maximum Subtree of the Same Color](/solution/3000-3099/3004.Maximum%20Subtree%20of%20the%20Same%20Color/README_EN.md)  |  `Tree`,`Depth-First Search`,`Array`,`Dynamic Programming`  |  Medium  |  🔒  |
 |  3005  |  [Count Elements With Maximum Frequency](/solution/3000-3099/3005.Count%20Elements%20With%20Maximum%20Frequency/README_EN.md)  |  `Array`,`Hash Table`,`Counting`  |  Easy  |  Weekly Contest 380  |
 |  3006  |  [Find Beautiful Indices in the Given Array I](/solution/3000-3099/3006.Find%20Beautiful%20Indices%20in%20the%20Given%20Array%20I/README_EN.md)  |  `Two Pointers`,`String`,`Binary Search`,`String Matching`,`Hash Function`,`Rolling Hash`  |  Medium  |  Weekly Contest 380  |
 |  3007  |  [Maximum Number That Sum of the Prices Is Less Than or Equal to K](/solution/3000-3099/3007.Maximum%20Number%20That%20Sum%20of%20the%20Prices%20Is%20Less%20Than%20or%20Equal%20to%20K/README_EN.md)  |  `Bit Manipulation`,`Binary Search`,`Dynamic Programming`  |  Medium  |  Weekly Contest 380  |
@@ -3031,15 +3031,15 @@ Press <kbd>Control</kbd> + <kbd>F</kbd>(or <kbd>Command</kbd> + <kbd>F</kbd> on
 |  3020  |  [Find the Maximum Number of Elements in Subset](/solution/3000-3099/3020.Find%20the%20Maximum%20Number%20of%20Elements%20in%20Subset/README_EN.md)  |  `Array`,`Hash Table`,`Enumeration`  |  Medium  |  Weekly Contest 382  |
 |  3021  |  [Alice and Bob Playing Flower Game](/solution/3000-3099/3021.Alice%20and%20Bob%20Playing%20Flower%20Game/README_EN.md)  |  `Math`  |  Medium  |  Weekly Contest 382  |
 |  3022  |  [Minimize OR of Remaining Elements Using Operations](/solution/3000-3099/3022.Minimize%20OR%20of%20Remaining%20Elements%20Using%20Operations/README_EN.md)  |  `Greedy`,`Bit Manipulation`,`Array`  |  Hard  |  Weekly Contest 382  |
-|  3023  |  [Find Pattern in Infinite Stream I](/solution/3000-3099/3023.Find%20Pattern%20in%20Infinite%20Stream%20I/README_EN.md)  |    |  Medium  |  🔒  |
-|  3024  |  [Type of Triangle II](/solution/3000-3099/3024.Type%20of%20Triangle%20II/README_EN.md)  |    |  Easy  |  Biweekly Contest 123  |
-|  3025  |  [Find the Number of Ways to Place People I](/solution/3000-3099/3025.Find%20the%20Number%20of%20Ways%20to%20Place%20People%20I/README_EN.md)  |    |  Medium  |  Biweekly Contest 123  |
-|  3026  |  [Maximum Good Subarray Sum](/solution/3000-3099/3026.Maximum%20Good%20Subarray%20Sum/README_EN.md)  |    |  Medium  |  Biweekly Contest 123  |
-|  3027  |  [Find the Number of Ways to Place People II](/solution/3000-3099/3027.Find%20the%20Number%20of%20Ways%20to%20Place%20People%20II/README_EN.md)  |    |  Hard  |  Biweekly Contest 123  |
-|  3028  |  [Ant on the Boundary](/solution/3000-3099/3028.Ant%20on%20the%20Boundary/README_EN.md)  |    |  Easy  |  Weekly Contest 383  |
-|  3029  |  [Minimum Time to Revert Word to Initial State I](/solution/3000-3099/3029.Minimum%20Time%20to%20Revert%20Word%20to%20Initial%20State%20I/README_EN.md)  |    |  Medium  |  Weekly Contest 383  |
-|  3030  |  [Find the Grid of Region Average](/solution/3000-3099/3030.Find%20the%20Grid%20of%20Region%20Average/README_EN.md)  |    |  Medium  |  Weekly Contest 383  |
-|  3031  |  [Minimum Time to Revert Word to Initial State II](/solution/3000-3099/3031.Minimum%20Time%20to%20Revert%20Word%20to%20Initial%20State%20II/README_EN.md)  |    |  Hard  |  Weekly Contest 383  |
+|  3023  |  [Find Pattern in Infinite Stream I](/solution/3000-3099/3023.Find%20Pattern%20in%20Infinite%20Stream%20I/README_EN.md)  |  `Array`,`String`,`String Matching`,`Sliding Window`  |  Medium  |  🔒  |
+|  3024  |  [Type of Triangle II](/solution/3000-3099/3024.Type%20of%20Triangle%20II/README_EN.md)  |  `Array`,`Math`,`Sorting`  |  Easy  |  Biweekly Contest 123  |
+|  3025  |  [Find the Number of Ways to Place People I](/solution/3000-3099/3025.Find%20the%20Number%20of%20Ways%20to%20Place%20People%20I/README_EN.md)  |  `Geometry`,`Array`,`Math`,`Enumeration`,`Sorting`  |  Medium  |  Biweekly Contest 123  |
+|  3026  |  [Maximum Good Subarray Sum](/solution/3000-3099/3026.Maximum%20Good%20Subarray%20Sum/README_EN.md)  |  `Array`,`Hash Table`,`Prefix Sum`  |  Medium  |  Biweekly Contest 123  |
+|  3027  |  [Find the Number of Ways to Place People II](/solution/3000-3099/3027.Find%20the%20Number%20of%20Ways%20to%20Place%20People%20II/README_EN.md)  |  `Geometry`,`Array`,`Math`,`Enumeration`,`Sorting`  |  Hard  |  Biweekly Contest 123  |
+|  3028  |  [Ant on the Boundary](/solution/3000-3099/3028.Ant%20on%20the%20Boundary/README_EN.md)  |  `Array`,`Prefix Sum`,`Simulation`  |  Easy  |  Weekly Contest 383  |
+|  3029  |  [Minimum Time to Revert Word to Initial State I](/solution/3000-3099/3029.Minimum%20Time%20to%20Revert%20Word%20to%20Initial%20State%20I/README_EN.md)  |  `String`,`String Matching`,`Hash Function`,`Rolling Hash`  |  Medium  |  Weekly Contest 383  |
+|  3030  |  [Find the Grid of Region Average](/solution/3000-3099/3030.Find%20the%20Grid%20of%20Region%20Average/README_EN.md)  |  `Array`,`Matrix`  |  Medium  |  Weekly Contest 383  |
+|  3031  |  [Minimum Time to Revert Word to Initial State II](/solution/3000-3099/3031.Minimum%20Time%20to%20Revert%20Word%20to%20Initial%20State%20II/README_EN.md)  |  `String`,`String Matching`,`Hash Function`,`Rolling Hash`  |  Hard  |  Weekly Contest 383  |
 
 ## Copyright
 
