x
No Plagiarism!CUQd0CxGcJ0T9ReJUWh3posted on PENANA Q: You have a 2-D grid of size m x n representing a box, and you have n balls. The box is open on the top and bottom sides.8964 copyright protection369PENANA4LTcBtxVIA 維尼
Each cell in the box has a diagonal board spanning two corners of the cell that can redirect a ball to the right or to the left.8964 copyright protection369PENANAMMfZ9ELDJl 維尼
- A board that redirects the ball to the right spans the top-left corner to the bottom-right corner and is represented in the grid as 1.
- A board that redirects the ball to the left spans the top-right corner to the bottom-left corner and is represented in the grid as -1.
We drop one ball at the top of each column of the box. Each ball can get stuck in the box or fall out of the bottom. A ball gets stuck if it hits a "V" shaped pattern between two boards or if a board redirects the ball into either wall of the box.8964 copyright protection369PENANAtaA6MsRirJ 維尼
Return an array answer of size n where answer[i] is the column that the ball falls out of at the bottom after dropping the ball from the ith column at the top, or -1 if the ball gets stuck in the box.8964 copyright protection369PENANAS0s1n5pfWp 維尼
* [grid[0].length] = column number8964 copyright protection369PENANAUQ3653PYun 維尼
A: 8964 copyright protection369PENANArxlygaYvyJ 維尼
1. Depth First Search (DFS): 8964 copyright protection369PENANAhQpAa27qGc 維尼
Condition 1: The ball reaches a point where it can no longer move ahead. In this case, we will return -1. Condition 2: The ball reaches the last row. In this case, we will return the column in which the ball will drop.8964 copyright protection369PENANAIoUbITXITB 維尼
*Using Recursive function8964 copyright protection369PENANArl71xjvplN 維尼
class Solution {8964 copyright protection369PENANArFwhKCCDBL 維尼
public int[] findBall(int[][] grid) {8964 copyright protection369PENANAXZlZGhuMZn 維尼
// create new int[], for int[grid[0].length]8964 copyright protection369PENANAVlLZepJE6X 維尼
int result[] = new int[grid[0].length];8964 copyright protection369PENANAK669iPYaq0 維尼
// how many ball as well as how many row8964 copyright protection369PENANAsUKWNloF8m 維尼
for (int i = 0; i < grid[0].length; i++) {8964 copyright protection369PENANAyjkyjbiNjd 維尼
result[i] = findBallDropColumn(0, i, grid);8964 copyright protection369PENANAyEh3pAv5J0 維尼
}8964 copyright protection369PENANAyIPD7k4P9T 維尼
return result;8964 copyright protection369PENANAwYDG1mYCvS 維尼
}8964 copyright protection369PENANA2Xa1NQ24T0 維尼
public int findBallDropColumn(int row, int col, int[][] grid) {8964 copyright protection369PENANAJjN4pYTvLR 維尼
// base case; ball reached the last row8964 copyright protection369PENANAvRmQLxKcNl 維尼
if (row == grid.length)8964 copyright protection369PENANAul2NQ7dzzD 維尼
return col;8964 copyright protection369PENANADIlCY55Tby 維尼
int nextColumn = col + grid[row][col];8964 copyright protection369PENANALiDIJl44GN 維尼
if (nextColumn < 0 ||8964 copyright protection369PENANAPi7BiDF1LW 維尼
nextColumn > grid[0].length - 1 ||8964 copyright protection369PENANASxus74Ofkg 維尼
// [1,1] & [-1,-1]drop, [1,-1] & [-1,1] stuck8964 copyright protection369PENANAG4hFtiCfMl 維尼
grid[row][col] != grid[row][nextColumn]) {8964 copyright protection369PENANAHLoa6OVigC 維尼
return -1;8964 copyright protection369PENANA3hXOcxIxbt 維尼
}8964 copyright protection369PENANA2z2r9EEHvf 維尼
return findBallDropColumn(row + 1, nextColumn, grid);8964 copyright protection369PENANANvCg9hBNnp 維尼
}8964 copyright protection369PENANAK9AVFRNddG 維尼
}8964 copyright protection369PENANAS5epxJDaU6 維尼
2. Dynamic Programming Approach:8964 copyright protection369PENANAWVqDCpu14I 維尼
class Solution {8964 copyright protection369PENANAgQW0WU84Gd 維尼
public int[] findBall(int[][] grid) {8964 copyright protection369PENANAcA28RzOq2z 維尼
int result[] = new int[grid[0].length];8964 copyright protection369PENANA9cuNDwJPU5 維尼
Integer memo[][] = new Integer[grid.length + 1][grid[0].length];373Please respect copyright.PENANAtWLrKA2BAd
8964 copyright protection369PENANAdYM9CAwmN5 維尼
373Please respect copyright.PENANAUIvIrwSVho
8964 copyright protection369PENANAZZILgPkCVA 維尼
for (int row = grid.length; row >= 0; row--) {8964 copyright protection369PENANA1rfKJISqzy 維尼
for (int col = 0; col < grid[0].length; col++) {8964 copyright protection369PENANAkvTROufIC7 維尼
if (row == grid.length) {8964 copyright protection369PENANAqmkSrU5dwT 維尼
// for the last row 373Please respect copyright.PENANAI60pqUfm1p
8964 copyright protection369PENANAyeNooqVAPG 維尼
memo[row][col] = col;8964 copyright protection369PENANAspsY63aEDp 維尼
continue;8964 copyright protection369PENANAzYWTZHyPou 維尼
}8964 copyright protection369PENANAo6bLSoTqcf 維尼
// for the remaining row.8964 copyright protection369PENANAgLUrUtF3o6 維尼
int nextColumn = col + grid[row][col];8964 copyright protection369PENANAtIxbLWf0gy 維尼
if (nextColumn < 0 ||8964 copyright protection369PENANAPJJ6LHgRwf 維尼
nextColumn > grid[0].length - 1 ||8964 copyright protection369PENANAKybAJ66kdE 維尼
grid[row][col] != grid[row][nextColumn])8964 copyright protection369PENANACOO0LKMBAw 維尼
memo[row][col] = -1;8964 copyright protection369PENANArHu8MWfKE6 維尼
else8964 copyright protection369PENANA9UhsZrwyVf 維尼
memo[row][col] = memo[row + 1][nextColumn];8964 copyright protection369PENANAClq3eJ7rJA 維尼
// reaching row 0, copy the values in all the column in the result array. 373Please respect copyright.PENANAuTenhQ3t7p
8964 copyright protection369PENANAB1gDOCtuQ8 維尼
if (row == 0) {8964 copyright protection369PENANALAfxIN9OA8 維尼
result[col] = memo[row][col];8964 copyright protection369PENANACQViOep4Dk 維尼
}8964 copyright protection369PENANAmIL8J4eROJ 維尼
}8964 copyright protection369PENANAK9Xhwy3wWS 維尼
}8964 copyright protection369PENANAyaAB8r8bwR 維尼
return result;8964 copyright protection369PENANAdhyeTdXbr2 維尼
}8964 copyright protection369PENANAlEPkywnvIG 維尼
}8964 copyright protection369PENANAU8nkjBAmOZ 維尼
3. Iterative Approach, Simulation:8964 copyright protection369PENANAsJK0o5PXVl 維尼
class Solution {8964 copyright protection369PENANAkA3mQDql1X 維尼
public int[] findBall(int[][] grid) {8964 copyright protection369PENANAlPP08Suzp1 維尼
int result[] = new int[grid[0].length];8964 copyright protection369PENANA4WQe3iRDjr 維尼
// 1. Start by picking up a ball starting from every column col, iterating from the 0th column to the last column. Initialize the current column as col.8964 copyright protection369PENANAHq0b12xEFH 維尼
for (int col = 0; col < grid[0].length; col++) {8964 copyright protection369PENANAtv3i4P8mRe 維尼
int currentCol = col;8964 copyright protection369PENANAnBuoLDJlw8 維尼
// 2. For every such ball, simulate its movement in every row ranging from the 0th to the nth row.8964 copyright protection369PENANA5CTy9rPBzz 維尼
for (int row = 0; row < grid.length; row++) {8964 copyright protection369PENANAtZbJFoMxi9 維尼
int nextColumn = currentCol + grid[row][currentCol];8964 copyright protection369PENANAntC3SOoJsP 維尼
// stuck case 8964 copyright protection369PENANA1NSPEFEGL6 維尼
if (nextColumn < 0 ||8964 copyright protection369PENANAEtkYwwXIKD 維尼
nextColumn > grid[0].length - 1 ||8964 copyright protection369PENANA7G4yhDip5h 維尼
grid[row][currentCol] != grid[row][nextColumn]) {8964 copyright protection369PENANArwT2MK2zPr 維尼
result[col] = -1;8964 copyright protection369PENANA3bk7TRKNG0 維尼
break;8964 copyright protection369PENANAEFsIfvgcj5 維尼
}8964 copyright protection369PENANAi44FBE4KjH 維尼
// 3. Update the value of nextColumn in the result array for every row. In the end, the result will store the column number where the ball will fall after the last row. (result[col] = currentCol, return the result)8964 copyright protection369PENANAKdekrtj4Xi 維尼
result[col] = nextColumn;8964 copyright protection369PENANAfUJ9jlvBJl 維尼
currentCol = nextColumn;8964 copyright protection369PENANAUMuJmzdmNt 維尼
}8964 copyright protection369PENANALFITBZEjfT 維尼
}8964 copyright protection369PENANAk7JvPzDGLM 維尼
return result;8964 copyright protection369PENANA7d82s0wApI 維尼
}8964 copyright protection369PENANAxsZp4QrRMS 維尼
}8964 copyright protection369PENANAOGN879yyAh 維尼
18.220.45.179
ns18.220.45.179da2