Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.

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.

Suppose a sorted array is rotated at some pivot unknown to you beforehand.

1.Laravel在truncate表的时候，如果有外键，先把约束检查关掉再清空表。如：

Given a sorted array of integers, find the starting and ending position of a given target value.

Given an array and a value, remove all instances of that value in place and return the new length.

Follow up for "Remove Duplicates":What if duplicates are allowed at most twice?For example,Given

Given a sorted array, remove the duplicates in place such that each element appear only once and return the new length.

Given an index k, return the kth row of the Pascal's triangle.

Given an array containing n distinct numbers taken from 0, 1, 2, ..., n, find the one that is missing from the array.