862. Shortest Subarray with Sum at Least K
Given an integer array nums and an integer k, return the length of the shortest non-empty subarray of nums with a sum of at least k. If there is no such subarray, return -1.
A subarray is a contiguous part of an array.
There is a safe protected by a password. The password is a sequence of n digits where each digit can be in the range [0, k - 1].
The safe has a peculiar way of checking the password. When you enter in a sequence, it checks the most recent n digits that were entered each time you type a digit.
- For example, the correct password is “345” and you enter in “012345”:
- After typing 0, the most recent 3 digits is “0”, which is incorrect.
- After typing 1, the most recent 3 digits is “01”, which is incorrect.
- After typing 2, the most recent 3 digits is “012”, which is incorrect.
- After typing 3, the most recent 3 digits is “123”, which is incorrect.
- After typing 4, the most recent 3 digits is “234”, which is incorrect.
- After typing 5, the most recent 3 digits is “345”, which is correct and the safe unlocks.
Return any string of minimum length that will unlock the safe at some point of entering it.
847. Shortest Path Visiting All Nodes
You have an undirected, connected graph of n nodes labeled from 0 to n - 1. You are given an array graph where graph[i] is a list of all the nodes connected with node i by an edge.
Return the length of the shortest path that visits every node. You may start and stop at any node, you may revisit nodes multiple times, and you may reuse edges.
188. Best Time to Buy and Sell Stock IV
You are given an integer array prices where prices[i] is the price of a given stock on the ith day, and an integer k.
Find the maximum profit you can achieve. You may complete at most k transactions.
Note: You may not engage in multiple transactions simultaneously (i.e., you must sell the stock before you buy again).
There is an undirected connected tree with n nodes labeled from 0 to n - 1 and n - 1 edges.
You are given the integer n and the array edges where edges[i] = [ai, bi] indicates that there is an edge between nodes ai and bi in the tree.
Return an array answer of length n where answer[i] is the sum of the distances between the ith node in the tree and all other nodes.
Given an array of distinct integers arr, where arr is sorted in ascending order, return the smallest index i that satisfies arr[i] == i. If there is no such index, return -1.
123. Best Time to Buy and Sell Stock III
You are given an array prices where prices[i] is the price of a given stock on the ith day.
Find the maximum profit you can achieve. You may complete at most two transactions.
Note: You may not engage in multiple transactions simultaneously (i.e., you must sell the stock before you buy again).
235. Lowest Common Ancestor of a Binary Search Tree
Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST.
According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes p and q as the lowest node in T that has both p and q as descendants (where we allow a node to be a descendant of itself).”
653. Two Sum IV - Input is a BST
Given the root of a Binary Search Tree and a target number k, return true if there exist two elements in the BST such that their sum is equal to the given target.
171. Excel Sheet Column Number
Given a string columnTitle that represents the column title as appear in an Excel sheet, return its corresponding column number.
For example:
2
3
4
5
6
7
8
B -> 2
C -> 3
...
Z -> 26
AA -> 27
AB -> 28
...