74

Author: Alimov-8

Data Structure 1/74. Search a 2D matrix.md

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+
+
+## Binary Search one by one
+#### Runtime: 61 ms, faster than 20.87% of Python3
+#### Memory Usage: 15 MB, less than 35.15% of Python3
+```py
+class Solution:
+    def searchMatrix(self, matrix: List[List[int]], target: int) -> bool:
+        m = len(matrix) - 1
+        n = len(matrix[0]) - 1
+        start, end = 0, m
+        middle = m // 2
+        is_bound_exist = False
+        while start <= end:
+            print(start, middle, end)
+            if matrix[middle][0] <= target and target <= matrix[middle][n]:
+                matrix = matrix[middle]
+                is_bound_exist = True
+                break
+                    
+            elif matrix[middle][n] < target:
+                start = middle + 1
+                middle = (start + end) // 2
+            
+            else:
+                end = middle - 1
+                middle = (start + end) // 2
+        
+        if is_bound_exist:
+            start, end = 0, n
+            middle = n // 2
+            while start <= end:
+                if matrix[middle] == target :
+                    return True
+
+                elif matrix[middle] < target:
+                    start = middle + 1
+                    middle = (start + end) // 2
+
+                else:
+                    end = middle - 1
+                    middle = (start + end) // 2
+                  
+        return False
+
+```
+
+## Nested Binary Search
+#### Runtime: 58 ms, faster than 23.38% of Python3
+#### Memory Usage: 14.9 MB, less than 35.15% of Python3
+```py
+class Solution:
+    def searchMatrix(self, matrix: List[List[int]], target: int) -> bool:
+        m = len(matrix) - 1
+        n = len(matrix[0]) - 1
+        start, end = 0, m
+        middle = m // 2
+        while start <= end:
+            if matrix[middle][0] <= target and target <= matrix[middle][n]:
+                matrix = matrix[middle]
+                start, end = 0, n
+                middle = n // 2
+                while start <= end:
+                    if matrix[middle] == target :
+                        return True
+
+                    elif matrix[middle] < target:
+                        start = middle + 1
+                        middle = (start + end) // 2
+
+                    else:
+                        end = middle - 1
+                        middle = (start + end) // 2
+                return False
+                    
+            elif matrix[middle][n] < target:
+                start = middle + 1
+                middle = (start + end) // 2
+            
+            else:
+                end = middle - 1
+                middle = (start + end) // 2
+                
+        return False
+
+```
+
+## 2D array -> 1D and Binary search
+#### Runtime: 71 ms, faster than 13.03% of Python3
+#### Memory Usage: 14.7 MB, less than 64.82% of Python3
+```py
+class Solution:
+    def searchMatrix(self, matrix: List[List[int]], target: int) -> bool:
+        matrix = [val 
+                  for sublist in matrix
+                  for val in sublist]
+        
+        m = len(matrix) - 1
+        start, end = 0, m
+        middle = m // 2
+        
+        while start <= end:
+            if matrix[middle] == target :
+                return True
+
+            elif matrix[middle] < target:
+                start = middle + 1
+                middle = (start + end) // 2
+
+            else:
+                end = middle - 1
+                middle = (start + end) // 2
+        return False
+```