174. Dungeon Game
The demons had captured the princess and imprisoned her in the bottom-right corner of a dungeon. The dungeon consists of m x n rooms laid out in a 2D grid. Our valiant knight was initially positioned in the top-left room and must fight his way through dungeon to rescue the princess.
Ref: Daniel J. Velleman. (2019). HOW TO PROVE IT (3th ed., pp. 1-6). Cambridge University Press.
Given an integer n, return the number of trailing zeroes in n!.
Note that n! = n * (n - 1) * (n - 2) * ... * 3 * 2 * 1.
172. Factorial Trailing Zeroes
Ref: labuladong 题解
There are n gas stations along a circular route, where the amount of gas at the ith station is gas[i].
You have a car with an unlimited gas tank and it costs cost[i] of gas to travel from the ith station to its next (i + 1)th station. You begin the journey with an empty tank at one of the gas stations.
Given two integer arrays gas and cost, return the starting gas station's index if you can travel around the circuit once in the clockwise direction, otherwise return -1. If there exists a solution, it is guaranteed to be unique
134. Gas Station
Ref: Bernard Kolman, Robert C. Busby & Sharon Cutler Ros. (2014). Relations and Digraph. Discrete Mathematical Structures (6th ed., pp. 139-204). Pearson.
Academic Writting skills.
Ref: Bernard Kolman, Robert C. Busby & Sharon Cutler Ros. (2014). Relations and Digraph. Discrete Mathematical Structures (6th ed., pp. 139-204). Pearson.
Tricks when manipulating coordinates in algorithms.
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: i.e. you may buy at most k times and sell at most k times.
Note: You may not engage in multiple transactions simultaneously (i.e., you must sell the stock before you buy again).
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