摘要：
Given a list, rotate the list to the right bykplaces, wherekis non-negative.For example:Given1->2->3->4->5->NULLandk=2,return4->5->1->2->3->NULL.注意一些边界的处理，找到n-k+1个节点后处理移位。 1 /** 2 * Definition for singly-linked list. 3 * struct ListNode { 4 * int val; 5 * ListNode *next 阅读全文
摘要：
Validate if a given string is numeric.Some examples:"0"=>true" 0.1 "=>true"abc"=>false"1 a"=>false"2e10"=>trueNote:It is intended for the problem statement to be ambiguous. You should gather all requirements up front before implementin 阅读全文
摘要：
Given a string containing just the characters'(',')','{','}','['and']', determine if the input string is valid.The brackets must close in the correct order,"()"and"()[]{}"are all valid but"(]"and"([)]"are not.利用一 阅读全文
摘要：
Implementint sqrt(int x).Compute and return the square root ofx.牛顿迭代 1 class Solution { 2 public: 3 int sqrt(int x) { 4 // Start typing your C/C++ solution below 5 // DO NOT write int main() function 6 double ans = x; 7 8 while(abs(ans * ans - x) > 0.0001... 阅读全文
摘要：
Given an integern, generate a square matrix filled with elements from 1 ton2in spiral order.For example,Givenn=3,You should return the following matrix:[ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ]]继续DFS 1 class Solution { 2 private: 3 int step[4][2]; 4 bool canUse[100][100]; 5 public: 6 void ... 阅读全文
摘要：
Given a matrix ofmxnelements (mrows,ncolumns), return all elements of the matrix in spiral order.For example,Given the following matrix:[ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ]]You should return[1,2,3,6,9,8,7,4,5].开一个数组用来保存，之前这个单元是否被使用过，并配合边界判断，DFS，最后得出结果。空间复杂度O(n*m)，时间O(n*m) 1 class Solution { 2 pri 阅读全文
摘要：
Given amxnmatrix, if an element is 0, set its entire row and column to 0. Do it in place.Follow up:Did you use extra space?A straight forward solution using O(mn) space is probably a bad idea.A simple improvement uses O(m+n) space, but still not the best solution.Could you devise a constant space so 阅读全文
摘要：
Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.You may assume no duplicates in the array.Here are few examples.[1,3,5,6], 5 → 2[1,3,5,6], 2 → 1[1,3,5,6], 7 → 4[1,3,5,6], 0 → 0二分搜索的修改版 1 class S 阅读全文
摘要：
Mergeksorted linked lists and return it as one sorted list. Analyze and describe its complexity.类似于Merge Sort的方法做k-1次 1 /** 2 * Definition for singly-linked list. 3 * struct ListNode { 4 * int val; 5 * ListNode *next; 6 * ListNode(int x) : val(x), next(NULL) {} 7 * }; 8 */ 9 class... 阅读全文