Given an array of n integers nums and an integer target, find the number of index triplets i, j, k with 0 <= i < j < k < n that satisfy the condition nums[i] + nums[j] + nums[k] < target.
Given an array of n integers nums and an integer target, find the number of index triplets i, j, k with 0 <= i < j < k < n that satisfy the condition nums[i] + nums[j] + nums[k] < target.
1352. Product of the Last K Numbers
Design an algorithm that accepts a stream of integers and retrieves the product of the last k integers of the stream.
Implement the ProductOfNumbers class:
- ProductOfNumbers() Initializes the object with an empty stream.
- void add(int num) Appends the integer num to the stream.
- int getProduct(int k) Returns the product of the last k numbers in the current list. You can assume that always the current list has at least k numbers.
The test cases are generated so that, at any time, the product of any contiguous sequence of numbers will fit into a single 32-bit integer without overflowing.
549. Binary Tree Longest Consecutive Sequence II
Given the root of a binary tree, return the length of the longest consecutive path in the tree.
A consecutive path is a path where the values of the consecutive nodes in the path differ by one. This path can be either increasing or decreasing.
- For example, [1,2,3,4] and [4,3,2,1] are both considered valid, but the path [1,2,4,3] is not valid.
On the other hand, the path can be in the child-Parent-child order, where not necessarily be parent-child order.
1254. Number of Closed Islands
Given a 2D grid consists of 0s (land) and 1s (water). An island is a maximal 4-directionally connected group of 0s and a closed island is an island totally (all left, top, right, bottom) surrounded by 1s.
Return the number of closed islands.
Given an integer array of size n, find all elements that appear more than ⌊ n/3 ⌋ times.
1504. Count Submatrices With All Ones
Given an m x n binary matrix mat, return the number of submatrices that have all ones.
You are given a network of n nodes, labeled from 1 to n. You are also given times, a list of travel times as directed edges times[i] = (ui, vi, wi), where ui is the source node, vi is the target node, and wi is the time it takes for a signal to travel from source to target.
We will send a signal from a given node k. Return the time it takes for all the n nodes to receive the signal. If it is impossible for all the n nodes to receive the signal, return -1.
Given a non-negative integer represented as a linked list of digits, plus one to the integer.
The digits are stored such that the most significant digit is at the head of the list.
A word’s generalized abbreviation can be constructed by taking any number of non-overlapping and non-adjacent substrings and replacing them with their respective lengths.
- For example, “abcde” can be abbreviated into:
- “a3e” (“bcd” turned into “3”)
- “1bcd1” (“a” and “e” both turned into “1”)
- “5” (“abcde” turned into “5”)
- “abcde” (no substrings replaced)
- However, these abbreviations are invalid:
- “23” (“ab” turned into “2” and “cde” turned into “3”) is invalid as the substrings chosen are adjacent.
- “22de” (“ab” turned into “2” and “bc” turned into “2”) is invalid as the substring chosen overlap.
Given a string word, return a list of all the possible generalized abbreviations of word. Return the answer in any order.
1631. Path With Minimum Effort
You are a hiker preparing for an upcoming hike. You are given heights, a 2D array of size rows x columns, where heights[row][col] represents the height of cell (row, col). You are situated in the top-left cell, (0, 0), and you hope to travel to the bottom-right cell, (rows-1, columns-1) (i.e., 0-indexed). You can move up, down, left, or right, and you wish to find a route that requires the minimum effort.
A route’s effort is the maximum absolute difference in heights between two consecutive cells of the route.
Return the minimum effort required to travel from the top-left cell to the bottom-right cell.