optimized: search element in 2D matrix in O(n) time

Author: NirmalSilwal

CodingBlocks Training/Day14/searchMatrix3.java

@@ -0,0 +1,36 @@
+package Lecture14;
+
+public class searchMatrix3 {
+
+	public static void main(String[] args) {
+
+		int[][] arr = { { 10, 20, 30, 40 }, 
+						{ 11, 21, 31, 41 },
+						{ 12, 22, 32, 42 }, 
+						{ 13, 23, 33, 43 } };
+
+		System.out.println(staircase(arr, 22)); // true
+		System.out.println(staircase(arr, 10)); // true
+		System.out.println(staircase(arr, 42)); // true
+		System.out.println(staircase(arr, 23)); // true
+		System.out.println(staircase(arr, 13)); // true
+		System.out.println(staircase(arr, 2)); // false
+
+	}
+
+	public static boolean staircase(int[][] arr, int key) {
+		int row = 0, col = arr.length - 1;
+
+		while (row < arr.length && col >= 0) {
+			if (arr[row][col] == key) {
+				return true;
+			} else if (key > arr[row][col]) {
+				row++;
+			} else {
+				col--;
+			}
+		}
+
+		return false;
+	}
+}