在路上的豆丁

摘要： A matrix is Toeplitz if every diagonal from top-left to bottom-right has the same element. Now given an M x N matrix, return True if and only if the m 阅读全文

摘要： We have some permutation A of [0, 1, ..., N - 1], where N is the length of A. The number of (global) inversions is the number of i < j with 0 <= i < j 阅读全文

摘要： Given string S and a dictionary of words words, find the number of words[i] that is a subsequence of S. Example : Input: S = "abcde" words = ["a", "bb 阅读全文

摘要： We are given an array A of positive integers, and two positive integers L and R (L <= R). Return the number of (contiguous, non-empty) subarrays such 阅读全文

摘要： Some people will make friend requests. The list of their ages is given and ages[i] is the age of the ith person. Person A will NOT friend request pers 阅读全文

摘要： In a string S of lowercase letters, these letters form consecutive groups of the same character. For example, a string like S = "abbxxxxzyy" has the g 阅读全文

摘要： Given a binary matrix A, we want to flip the image horizontally, then invert it, and return the resulting image. To flip an image horizontally means t 阅读全文

摘要： A 3 x 3 magic square is a 3 x 3 grid filled with distinct numbers from 1 to 9 such that each row, column, and both diagonals all have the same sum. Gi 阅读全文

摘要： In a row of seats, 1 represents a person sitting in that seat, and 0 represents that the seat is empty. There is at least one empty seat, and at least 阅读全文

摘要： Given a matrix A, return the transpose of A. The transpose of a matrix is the matrix flipped over it's main diagonal, switching the row and column ind 阅读全文