feat: 2074. Reverse Nodes in Even Length Groups : 链表

Author: upupming

leetcode/残酷刷题/2074. Reverse Nodes in Even Length Groups.js

@@ -0,0 +1,40 @@
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val, next) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.next = (next===undefined ? null : next)
+ * }
+ */
+/**
+ * @param {ListNode} head
+ * @return {ListNode}
+ */
+const reverseEvenLengthGroups = function (head) {
+  let a = head; let sz = 0
+  while (a) sz++, a = a.next
+  console.log(sz)
+  let x = null; let y = head
+  for (let i = 1; sz > 0; sz -= i, i++) {
+    const len = Math.min(i, sz)
+    let a = y; let b = a.next
+    // console.log('case1', i, len, sz, x?.val, y?.val, a?.val, b?.val)
+    for (let j = 0; j < len - 1; j++) {
+      if (len % 2 === 0) {
+        const c = b.next
+        b.next = a
+        a = b, b = c
+      } else {
+        a = a.next
+      }
+    }
+    if (len % 2 === 0) {
+      // console.log('case2', i, sz, len, x?.val, y.val, a.val, b?.val)
+      x.next = a, y.next = b
+      x = y, y = x.next
+    } else {
+      x = a, y = x.next
+    }
+  }
+
+  return head
+}

leetcode/残酷刷题/README.md

@@ -172,6 +172,7 @@
 - 206. Reverse Linked List
 - 92. Reverse Linked List II
 - 25. Reverse Nodes in k-Group
+- 2074. Reverse Nodes in Even Length Groups
 
 ## Links