Ruizhi Ma's Blog

Problem 86

Partition List

问题描述 https://leetcode.com/problems/partition-list/ 代码 /** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode(int x) { val = x; }...

Posted by Ruizhi Ma on August 12, 2019

Problem 83

Remove Duplicates from Sorted List

问题描述 https://leetcode.com/problems/remove-duplicates-from-sorted-list/ 解决思路如果当前节点的值和下一个节点的值相等，就将下个节点指向下下个节点；否则将当前节点指向下个节点。代码 /** * Definition for singly-linked list. * public class ListNode {...

Posted by Ruizhi Ma on August 11, 2019

Problem 82

Rmove Duplicate from Sorted Array II

问题描述 https://leetcode.com/problems/remove-duplicates-from-sorted-list-ii/ 解决思路不断的比较当前节点与前一个节点和下一个节点的值，若相等，则往后移动；不想等，设为realNode 代码 /** * Definition for singly-linked list. * public class ListNo...

Posted by Ruizhi Ma on August 11, 2019

Problem 61

Rotate List

问题描述 https://leetcode.com/problems/rotate-list/ 解决思路用双指针fast和slow指向head，先用fast算出listNode的长度len，然后先移动fast到k%len的位置，然后将slow和fast同时向后移动k%len。最后此时slow指向的应该是新listNode的尾节点（除去null先不谈），slow.next应该是新节点的头节...

Posted by Ruizhi Ma on July 30, 2019

Problem 60

Permutation Sequence

问题描述 https://leetcode.com/problems/permutation-sequence/ 解决思路一（Time Out）先用递归，回溯，讲全排列集合写出来，然后再找到对应的第几个，转为String类型。问题解惑如何将List转为String? 首先用迭代器，将List中的每一个元素拿出来，再将他们通过append，加到StringBuilder类型str...

Posted by Ruizhi Ma on July 30, 2019

Problem 56

Merge Intervals

问题描述 https://leetcode.com/problems/merge-intervals/ 解决思路先将所给的每个数组，按照首元素进行排序，然后分情况讨论：上一个数组首元素等于当前数组首元素的时候，若上一个数组的尾元素小于当前数组尾元素，则将当前数组尾元素，设置为新数组的尾元素。上一个数组首元素小于当前数组首元素的时候，分下面的情况： 2.1 上一个数组的尾元素...

Posted by Ruizhi Ma on July 29, 2019

Problem 55

Jump Game

问题描述 https://leetcode.com/problems/jump-game/submissions/ 解决思路举个例子：[2,3,1,4,3] 一开始在2的位置，此时既可以跳到3和1，然后在3的地方可以跳到1,4,3.此时已经到队尾，返回true.解题核心思路就是用reach记录下能到达的最远距离（每次迭代的时候，在上一次的reach和当前nums[i]+i中取得最大值），...

Posted by Ruizhi Ma on July 29, 2019

Problem 59

Spiral Matrix II

问题描述 https://leetcode.com/problems/spiral-matrix-ii/ 解决思路这题和54基本差不多，思路一样的，需要单独处理一下中间会剩下一个的情况。代码 class Solution { public int[][] generateMatrix(int n) { int[][] res = new int[n][n]; ...

Posted by Ruizhi Ma on July 28, 2019

Problem 58

Length of Last Word

问题描述 Given a string s consists of upper/lower-case alphabets and empty space characters ‘ ‘, return the length of last word in the string. If the last word does not exist, return 0. Note: A word ...