Search a 2D matrix

Leetcode - 74 # Search a 2D Matrix.py

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+# Solution-1
+# Check which row target element is and then apply Binary Search in that particular row
+# Time complexity m*log(n)
+
+class Solution:
+    def searchMatrix(self, matrix: List[List[int]], target: int) -> bool:
+        m = len(matrix)  # number of rows
+        n = len(matrix[0])  # number of cols
+
+        for row in range(m):
+            # if element is in a row
+            if target >= matrix[row][0] and target <= matrix[row][-1]:
+                # Perform Binary Search
+                left = 0
+                right = n - 1
+
+                while left <= right:
+                    mid = (left + right) // 2
+
+                    if matrix[row][mid] == target:
+                        return True
+
+                    elif matrix[row][mid] < target:
+                        left = mid + 1
+
+                    else:
+                        right = mid - 1
+        return False
+
+
+# Solution-2
+# In above solution, we are checking all rows
+# we know all rows are also Sorted
+# So we can apply Binary Search in Rows as well, to find the exact row
+# Then apply Binary Search in that row (to find target) - same as above.
+
+class Solution:
+    def searchMatrix(self, matrix: List[List[int]], target: int) -> bool:
+        m = len(matrix)  # number of rows
+        n = len(matrix[0])  # number of cols
+
+        top, bottom = 0, n - 1
+
+        # Apply Binary search on rows to find in whc=ich row
+        # element resides
+        while top <= bottom:
+            row = (top + bottom) // 2
+            if target > matrix[row][-1]:
+                top = row + 1
+            elif target < matrix[row][0]:
+                bottom = row - 1
+            else:
+                break
+
+        # Once we find the row
+        # apply Binary Search in that row.
+        if top <= bottom:
+            row = (top + bottom) // 2
+            left, right = 0, cols - 1
+            while left <= right:
+                mid = (left + right) // 2
+                if matrix[row][mid] == target:
+                    return True
+                elif matrix[row][mid] < target:
+                    left = mid + 1
+                else:
+                    right = mid - 1
+
+        return False