LeetCode 链表

LeetCode 链表简单题 可直接本地运行的 JS 版本每道题都包含链表节点构造函数数组转链表 / 链表转数组方便本地调试完整可运行代码测试用例你直接复制到浏览器控制台 / Node.js 就能跑不用改任何东西先写通用工具函数所有题都能用// 1. 链表节点构造函数 function ListNode(val, next) { this.val val undefined ? 0 : val; this.next next undefined ? null : next; } // 2. 数组 链表 function arrayToList(arr) { let dummy new ListNode(); let cur dummy; for (let num of arr) { cur.next new ListNode(num); cur cur.next; } return dummy.next; } // 3. 链表 数组方便打印看结果 function listToArray(head) { let res []; while (head) { res.push(head.val); head head.next; } return res; }下面所有题直接复制就能调试1. 反转链表 206function reverseList(head) { let prev null; let cur head; while (cur) { let next cur.next; cur.next prev; prev cur; cur next; } return prev; } // 测试 let head arrayToList([1,2,3,4,5]); console.log(listToArray(reverseList(head))); // [5,4,3,2,1]2. 合并两个有序链表 21function mergeTwoLists(l1, l2) { let dummy new ListNode(); let cur dummy; while (l1 l2) { if (l1.val l2.val) { cur.next l1; l1 l1.next; } else { cur.next l2; l2 l2.next; } cur cur.next; } cur.next l1 || l2; return dummy.next; } // 测试 let l1 arrayToList([1,2,4]); let l2 arrayToList([1,3,4]); console.log(listToArray(mergeTwoLists(l1, l2))); // [1,1,2,3,4,4]3. 删除排序链表中的重复元素 83function deleteDuplicates(head) { let cur head; while (cur cur.next) { if (cur.val cur.next.val) { cur.next cur.next.next; } else { cur cur.next; } } return head; } // 测试 let head arrayToList([1,1,2,3,3]); console.log(listToArray(deleteDuplicates(head))); // [1,2,3]4. 环形链表 141function hasCycle(head) { let slow head, fast head; while (fast fast.next) { slow slow.next; fast fast.next.next; if (slow fast) return true; } return false; } // 测试 let head arrayToList([3,2,0,-4]); head.next.next.next head; // 造环 console.log(hasCycle(head)); // true5. 链表的中间节点 876function middleNode(head) { let slow head, fast head; while (fast fast.next) { slow slow.next; fast fast.next.next; } return slow; } // 测试 let head arrayToList([1,2,3,4,5]); console.log(listToArray(middleNode(head))); // [3,4,5]6. 删除链表的倒数第 N 个节点 19function removeNthFromEnd(head, n) { let dummy new ListNode(0, head); let fast dummy, slow dummy; for (let i 0; i n; i) fast fast.next; while (fast) { fast fast.next; slow slow.next; } slow.next slow.next.next; return dummy.next; } // 测试 let head arrayToList([1,2,3,4,5]); console.log(listToArray(removeNthFromEnd(head, 2))); // [1,2,3,5]7. 回文链表 234function isPalindrome(head) { let slow head, fast head; let prev null; while (fast fast.next) { fast fast.next.next; let next slow.next; slow.next prev; prev slow; slow next; } while (prev) { if (prev.val ! slow.val) return false; prev prev.next; slow slow.next; } return true; } // 测试 let head arrayToList([1,2,2,1]); console.log(isPalindrome(head)); // true8. 相交链表 160function getIntersectionNode(headA, headB) { let a headA, b headB; while (a ! b) { a a ? a.next : headB; b b ? b.next : headA; } return a; } // 测试逻辑略本地可直接跑 LeetCode 用例9. 移除链表元素 203function removeElements(head, val) { let dummy new ListNode(0, head); let cur dummy; while (cur.next) { if (cur.next.val val) { cur.next cur.next.next; } else { cur cur.next; } } return dummy.next; } // 测试 let head arrayToList([1,2,6,3,4,5,6]); console.log(listToArray(removeElements(head, 6))); // [1,2,3,4,5]本地怎么用复制最上面通用工具函数复制任意一道题运行 → 自动出结果超级方便