[LeetCode] The Maze III 迷宫之三

There is a ball in a maze with empty spaces and walls. The ball can go through empty spaces by rolling up (u), down (d), left (l) or right (r), but it won‘t stop rolling until hitting a wall. When the ball stops, it could choose the next direction. There is also a hole in this maze. The ball will drop into the hole if it rolls on to the hole.

Given the ball position, the hole position and the maze, find out how the ball could drop into the hole by moving the shortest distance. The distance is defined by the number of empty spaces traveled by the ball from the start position (excluded) to the hole (included). Output the moving directions by using ‘u‘, ‘d‘, ‘l‘ and ‘r‘. Since there could be several different shortest ways, you should output the lexicographically smallest way. If the ball cannot reach the hole, output "impossible".

The maze is represented by a binary 2D array. 1 means the wall and 0 means the empty space. You may assume that the borders of the maze are all walls. The ball and the hole coordinates are represented by row and column indexes.

Example 1

Input 1: a maze represented by a 2D array

0 0 0 0 0
1 1 0 0 1
0 0 0 0 0
0 1 0 0 1
0 1 0 0 0

Input 2: ball coordinate (rowBall, colBall) = (4, 3)
Input 3: hole coordinate (rowHole, colHole) = (0, 1)

Output: "lul"
Explanation: There are two shortest ways for the ball to drop into the hole.
The first way is left -> up -> left, represented by "lul".
The second way is up -> left, represented by ‘ul‘.
Both ways have shortest distance 6, but the first way is lexicographically smaller because ‘l‘ < ‘u‘. So the output is "lul".

Example 2

Input 1: a maze represented by a 2D array

0 0 0 0 0
1 1 0 0 1
0 0 0 0 0
0 1 0 0 1
0 1 0 0 0

Input 2: ball coordinate (rowBall, colBall) = (4, 3)
Input 3: hole coordinate (rowHole, colHole) = (3, 0)
Output: "impossible"
Explanation: The ball cannot reach the hole.

Note:

  1. There is only one ball and one hole in the maze.
  2. Both the ball and hole exist on an empty space, and they will not be at the same position initially.
  3. The given maze does not contain border (like the red rectangle in the example pictures), but you could assume the border of the maze are all walls.
  4. The maze contains at least 2 empty spaces, and the width and the height of the maze won‘t exceed 30.

s

时间： 2024-10-13 01:14:31

[LeetCode] The Maze III 迷宫之三的相关文章

[LeetCode] The Maze II 迷宫之二

There is a ball in a maze with empty spaces and walls. The ball can go through empty spaces by rolling up, down, left or right, but it won't stop rolling until hitting a wall. When the ball stops, it could choose the next direction. Given the ball's 

3299: [USACO2011 Open]Corn Maze玉米迷宫

3299: [USACO2011 Open]Corn Maze玉米迷宫 Time Limit: 10 Sec  Memory Limit: 128 MBSubmit: 137  Solved: 59[Submit][Status][Discuss] Description 今年秋天,约翰带着奶牛们去玩玉米迷宫.迷宫可分成NxM个格子,有些格子种了玉 米,种宥玉米的格子无法通行. 迷宫的四条边界上都是种了玉米的格子,其屮只有一个格子 没种,那就是出口. 在这个迷宫里,有一些神奇的传送点6每个传送点

[LeetCode] Contains Duplicate III 包含重复值之三

Given an array of integers, find out whether there are two distinct indices i and j in the array such that the difference between nums[i] and nums[j] is at most t and the difference between i and j is at most k. 参考资料: https://leetcode.com/discuss/381

[LeetCode] Strobogrammatic Number III 对称数之三

A strobogrammatic number is a number that looks the same when rotated 180 degrees (looked at upside down). Write a function to count the total strobogrammatic numbers that exist in the range of low <= num <= high. For example,Given low = "50&qu

[LeetCode] Single Number III 单独的数字之三

Given an array of numbers nums, in which exactly two elements appear only once and all the other elements appear exactly twice. Find the two elements that appear only once. For example: Given nums = [1, 2, 1, 3, 2, 5], return [3, 5]. Note: The order

[LeetCode] Course Schedule III 课程清单之三

There are n different online courses numbered from 1 to n. Each course has some duration(course length) tand closed on dth day. A course should be taken continuously for t days and must be finished before or on the dth day. You will start at the 1st 

[LeetCode] Combination Sum III 组合之和之三

Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can be used and each combination should be a unique set of numbers. Ensure that numbers within the set are sorted in ascending order. Example 1

leetcode Single Number III

题目连接 https://leetcode.com/problems/single-number-iii/ Single Number III Description Given an array of numbers nums, in which exactly two elements appear only once and all the other elements appear exactly twice. Find the two elements that appear only

499.&#160;The Maze III

There is a ball in a maze with empty spaces and walls. The ball can go through empty spaces by rolling up (u), down (d), left (l) or right (r), but it won't stop rolling until hitting a wall. When the ball stops, it could choose the next direction. T