﻿ Java - Paths from top-left to bottom-right corner of a grid

# Java: Find possible unique paths considering some obstacles, from top-left corner to bottom-right corner of a specified grid

## Java Basic: Exercise-137 with Solution

Write a Java program to find possible unique paths considering some obstacles, from top-left corner to bottom-right corner of a given grid (m x n).

Note: You can move either down or right at any point in time and an obstacle and empty space is marked as 1 and 0 respectively in the grid. Sample grid:
int[][] obstacle_Grid ={
{0, 0, 0},
{0, 1, 0},
{0, 0, 0},
};

Sample Solution:

Java Code:

``````import java.util.*
public class Solution {
public static int uniquePaths_With_obstacle_Grid(int[][] obstacle_Grid) {
// Get the number of rows (m) in the obstacle grid
int m = obstacle_Grid.length;
if (m <= 0) {
return 0;
}
// Get the number of columns (n) in the obstacle grid
int n = obstacle_Grid[0].length;
if (n <= 0) {
return 0;
}
// Create a dynamic programming array to store unique paths
int[][] dp = new int[m + 1][n + 1];
dp[m][n - 1] = 1;

// Nested loops to iterate through the grid
for (int i = m - 1; i >= 0; --i) { // Start from the bottom row and move upwards
for (int j = n - 1; j >= 0; --j) { // Start from the rightmost column and move leftwards
// Calculate unique paths for the current cell based on obstacles
dp[i][j] = (obstacle_Grid[i][j] == 0) ? dp[i + 1][j] + dp[i][j + 1] : 0;
}
}
// Return the count of unique paths from top-left to bottom-right corner
return dp[0][0];
}

// Main method for testing the uniquePaths_With_obstacle_Grid function
public static void main(String[] args) {
int[][] obstacle_Grid ={
{0, 0, 0},
{0, 1, 0},
{0, 0, 0},
};
System.out.println("Unique paths from top-left corner to bottom-right corner of the said grid (considering some obstacles): "+uniquePaths_With_obstacle_Grid(obstacle_Grid));
}
}
```
```

Sample Output:

```Unique paths from top-left corner to bottom-right corner of the said grid (considering some obstacles): 2s
```

Flowchart:

Java Code Editor:

Company:

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.

﻿