Create Search_a_2D_Matrix_II.py

Author: Ram-95

Leetcode_30day_challenge/Search_a_2D_Matrix_II.py

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+# Solution - 1: For every row, apply Binary Search - Time: O(rows * log(cols))
+class Solution:
+    def searchMatrix(self, matrix: List[List[int]], target: int) -> bool:
+        rows, cols = len(matrix), len(matrix[0])
+        r,c = 0,0
+        while r < rows and c < cols:
+            start, end = matrix[r][0], matrix[r][-1]
+            if target in range(start, end+1):
+                low, high = 0, cols-1
+                while low <= high:
+                    mid = (low + high) // 2
+                    if target == matrix[r][mid]:
+                        return True
+                    elif target < matrix[r][mid]:
+                        high = mid-1
+                    else:
+                        low = mid+1
+            r += 1
+        return False
+
+
+# Solution - 2: Start from the Top-right element and move the row and col pointer appropriately - Time: O(rows + cols)
+class Solution:
+    def searchMatrix(self, matrix: List[List[int]], target: int) -> bool:
+        rows, cols = len(matrix), len(matrix[0])
+        r,c = 0, cols-1
+        """Idea: Start from top right element and keep applying Binary Search."""
+        while r < rows and c >= 0:
+            if target == matrix[r][c]:
+                return True
+            elif target < matrix[r][c]:
+                c -= 1
+            else:
+                r += 1
+        return False