backtracking - recursion: finds all possible maze path having some hu…

…rdles

CodingBlocks Training/Day12/mazePathWithHurdles.java

@@ -0,0 +1,87 @@
+package Lecture12;
+
+public class mazePathWithHurdles {
+
+	public static void main(String[] args) {
+
+		int[][] arr = { { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 9, 0, 0, 0 },
+				{ 0, 9, 0, 0 } };
+		// here 9 is the hurdle
+		System.out.println("given board: ");
+		displayMatrix(arr);
+		int currentRow = 0, currentCol = 0, endRow = 3, endCol = 3;
+		System.out.println("possible paths: \n");
+		printMazePathHurdle(arr, endRow, endCol, currentRow, currentCol);
+
+	}
+
+	public static void printMazePathHurdle(int[][] arr, int endRow, int endCol,
+			int currentRow, int currentCol) {
+
+		if (currentRow == endRow && currentCol == endCol) {
+			arr[currentRow][currentCol] = 1;
+			displayMatrix(arr);
+			return;
+		}
+		if (currentRow > endRow | currentCol > endCol) {
+			return;
+		}
+
+		if (arr[currentRow][currentCol] == 9) {
+			return; // back-track to previous cell
+		}
+
+		arr[currentRow][currentCol] = 1; // set to 1 to indicate the cell is
+											// traversed
+
+		printMazePathHurdle(arr, endRow, endCol, currentRow, currentCol + 1); // traverse
+																				// horizontally
+		printMazePathHurdle(arr, endRow, endCol, currentRow + 1, currentCol); // traverse
+																				// vertically
+		arr[currentRow][currentCol] = 1;
+	}
+
+	public static void displayMatrix(int[][] arr) {
+		for (int row = 0; row < arr[0].length; row++) {
+			for (int col = 0; col < arr[row].length; col++) {
+				System.out.print(arr[row][col]);
+			}
+			System.out.println();
+		}
+		System.out.println("--------------");
+	}
+}
+
+/*
+output:
+
+given board: 
+0090
+0090
+9000
+0900
+--------------
+possible paths: 
+
+1190
+0190
+9111
+0901
+--------------
+1190
+0190
+9111
+0911
+--------------
+1190
+1190
+9111
+0911
+--------------
+1190
+1190
+9111
+0911
+--------------
+
+*/