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No Plagiarism!FJ8uuYsJBxEXlOatC1nqposted 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 protection363PENANAApKsPepIlF 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 protection363PENANAUDQdgR6Jtm 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 protection363PENANAJ7fgglbb8c 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 protection363PENANAjnAabEtUeO 維尼
* [grid[0].length] = column number8964 copyright protection363PENANAMSTE1BJrE6 維尼
A: 8964 copyright protection363PENANA4BWzLNZCwW 維尼
1. Depth First Search (DFS): 8964 copyright protection363PENANA5BtCIengjv 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 protection363PENANAyLPzrJKdEE 維尼
*Using Recursive function8964 copyright protection363PENANAX8hFAtwymb 維尼
class Solution {8964 copyright protection363PENANARHnIKWRBrB 維尼
public int[] findBall(int[][] grid) {8964 copyright protection363PENANAsaFjTwIvmz 維尼
// create new int[], for int[grid[0].length]8964 copyright protection363PENANANy5wwAv0P8 維尼
int result[] = new int[grid[0].length];8964 copyright protection363PENANAh3uDJaoOE3 維尼
// how many ball as well as how many row8964 copyright protection363PENANAQB7fTfC9VW 維尼
for (int i = 0; i < grid[0].length; i++) {8964 copyright protection363PENANAzxZIcpigHc 維尼
result[i] = findBallDropColumn(0, i, grid);8964 copyright protection363PENANAqY1PnqOYN8 維尼
}8964 copyright protection363PENANAzoqC39CHcp 維尼
return result;8964 copyright protection363PENANAetuT9zNm18 維尼
}8964 copyright protection363PENANA6ZoQSA3B55 維尼
public int findBallDropColumn(int row, int col, int[][] grid) {8964 copyright protection363PENANAgBZ1RCgAhX 維尼
// base case; ball reached the last row8964 copyright protection363PENANANb0fXRdbeP 維尼
if (row == grid.length)8964 copyright protection363PENANAv6tS4WI0Gc 維尼
return col;8964 copyright protection363PENANALv9DVjFVKf 維尼
int nextColumn = col + grid[row][col];8964 copyright protection363PENANAs0iH9h3CfG 維尼
if (nextColumn < 0 ||8964 copyright protection363PENANAMn5vGFz0Qc 維尼
nextColumn > grid[0].length - 1 ||8964 copyright protection363PENANAU2ER6GLs2d 維尼
// [1,1] & [-1,-1]drop, [1,-1] & [-1,1] stuck8964 copyright protection363PENANAI4EkGYr8iO 維尼
grid[row][col] != grid[row][nextColumn]) {8964 copyright protection363PENANANYGaOGmUvS 維尼
return -1;8964 copyright protection363PENANArTsMPeKWVM 維尼
}8964 copyright protection363PENANAbCh7Fpv3lj 維尼
return findBallDropColumn(row + 1, nextColumn, grid);8964 copyright protection363PENANAuivL041bvS 維尼
}8964 copyright protection363PENANASW6w5w8NXr 維尼
}8964 copyright protection363PENANAcYyTRsUf3Z 維尼
2. Dynamic Programming Approach:8964 copyright protection363PENANAXf59tKfS4B 維尼
class Solution {8964 copyright protection363PENANA1jXVnn8Zid 維尼
public int[] findBall(int[][] grid) {8964 copyright protection363PENANAeHd2fjIsgd 維尼
int result[] = new int[grid[0].length];8964 copyright protection363PENANAR3AR4xWFbE 維尼
Integer memo[][] = new Integer[grid.length + 1][grid[0].length];367Please respect copyright.PENANAfOVGgz0y7a
8964 copyright protection363PENANAvwFUPlt2iW 維尼
367Please respect copyright.PENANAJ8V2Wi6xL3
8964 copyright protection363PENANA5ZME7xJdLp 維尼
for (int row = grid.length; row >= 0; row--) {8964 copyright protection363PENANATC7xbp5d2t 維尼
for (int col = 0; col < grid[0].length; col++) {8964 copyright protection363PENANAKyYoHGdRWY 維尼
if (row == grid.length) {8964 copyright protection363PENANAJidNUMqPQS 維尼
// for the last row 367Please respect copyright.PENANAUHY7CGNGJE
8964 copyright protection363PENANAjcpRnsD4hC 維尼
memo[row][col] = col;8964 copyright protection363PENANAXC2aga4FkY 維尼
continue;8964 copyright protection363PENANAr0013gzbRS 維尼
}8964 copyright protection363PENANAjmnnq9VjI3 維尼
// for the remaining row.8964 copyright protection363PENANAY7Ah5zJhQR 維尼
int nextColumn = col + grid[row][col];8964 copyright protection363PENANAV2VpcBYFQV 維尼
if (nextColumn < 0 ||8964 copyright protection363PENANAr7mAPzTwfJ 維尼
nextColumn > grid[0].length - 1 ||8964 copyright protection363PENANAuhuNSvzoFF 維尼
grid[row][col] != grid[row][nextColumn])8964 copyright protection363PENANA87X5jumx1l 維尼
memo[row][col] = -1;8964 copyright protection363PENANATMG6Ra2nad 維尼
else8964 copyright protection363PENANAHamhUHGpAc 維尼
memo[row][col] = memo[row + 1][nextColumn];8964 copyright protection363PENANAnmwttvOrBr 維尼
// reaching row 0, copy the values in all the column in the result array. 367Please respect copyright.PENANACF90yPlXOs
8964 copyright protection363PENANAax3Eh1tXPM 維尼
if (row == 0) {8964 copyright protection363PENANArlIAqsO47f 維尼
result[col] = memo[row][col];8964 copyright protection363PENANA08ghext0xX 維尼
}8964 copyright protection363PENANAuJFqnK1TeA 維尼
}8964 copyright protection363PENANAuqN3lPgKWP 維尼
}8964 copyright protection363PENANA8oyO4LAEzt 維尼
return result;8964 copyright protection363PENANAVXGfxeutSJ 維尼
}8964 copyright protection363PENANARoHUDm2Wgf 維尼
}8964 copyright protection363PENANAgjDvziAyLe 維尼
3. Iterative Approach, Simulation:8964 copyright protection363PENANASoFyzTaZVB 維尼
class Solution {8964 copyright protection363PENANAJOuSwS0iRK 維尼
public int[] findBall(int[][] grid) {8964 copyright protection363PENANAmz2SGNOtWT 維尼
int result[] = new int[grid[0].length];8964 copyright protection363PENANAn5Jl2i2caV 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 protection363PENANAxl3cHzHK3e 維尼
for (int col = 0; col < grid[0].length; col++) {8964 copyright protection363PENANAzOqGe6eg9g 維尼
int currentCol = col;8964 copyright protection363PENANApoaNtYUj8i 維尼
// 2. For every such ball, simulate its movement in every row ranging from the 0th to the nth row.8964 copyright protection363PENANAmNJ5uFVLbj 維尼
for (int row = 0; row < grid.length; row++) {8964 copyright protection363PENANAYiXE6vwJsb 維尼
int nextColumn = currentCol + grid[row][currentCol];8964 copyright protection363PENANAhRjg4ECgWe 維尼
// stuck case 8964 copyright protection363PENANAgGofOVpJxc 維尼
if (nextColumn < 0 ||8964 copyright protection363PENANAONzvFh269P 維尼
nextColumn > grid[0].length - 1 ||8964 copyright protection363PENANAUU23Lm6V8c 維尼
grid[row][currentCol] != grid[row][nextColumn]) {8964 copyright protection363PENANAWtXBgxYvoU 維尼
result[col] = -1;8964 copyright protection363PENANAnUlzSpyqyZ 維尼
break;8964 copyright protection363PENANAs7WtyUdTc0 維尼
}8964 copyright protection363PENANAHo5gHqXIFe 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 protection363PENANATcjmfCIegl 維尼
result[col] = nextColumn;8964 copyright protection363PENANAxZAdK8p7B9 維尼
currentCol = nextColumn;8964 copyright protection363PENANABMjXLe13NC 維尼
}8964 copyright protection363PENANAYOi4LlSw7R 維尼
}8964 copyright protection363PENANAXySIHfrhuZ 維尼
return result;8964 copyright protection363PENANAvrMT8NIJMK 維尼
}8964 copyright protection363PENANA9EjVVRmXx7 維尼
}8964 copyright protection363PENANAPOFxb2Oxv0 維尼
18.117.101.118
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