feat: addgrpa

content/skTa4V7n8H8.md

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+---
+title: "note skta4v7n8h8"
+date: 2025-10-31T20:24:35+05:30
+draft: false
+---
+
+# GrPA 1
+
+```python
+def swap(arr, i, j):
+    arr[i], arr[j] = arr[j], arr[i]
+
+
+def max_heapify(arr, end, current):
+    left = 2 * current + 1
+    right = left + 1
+    largest = current
+
+    if left < end and arr[left] > arr[largest]:
+        largest = left
+    if right < end and arr[right] > arr[largest]:
+        largest = right
+
+    if largest != current:
+        swap(arr, current, largest)
+        max_heapify(arr, end, largest)
+
+
+def mergeKLists(arr):
+    arr = [value for subarray in arr for value in subarray]
+    n = len(arr)
+    for i in reversed(range(n // 2)):
+        max_heapify(arr, n, i)
+
+    for i in range(n-1,0,-1):
+        swap(arr, 0, i)
+        max_heapify(arr, i, 0)
+    return arr
+```
+
+# GrPA 2
+
+
+```python
+def maxLessThan(root, x):
+    floor = None
+    while not root.isempty():
+        if root.value > x:
+            root = root.left
+    
+        elif root.value <= x:
+            floor = root.value
+            root = root.right
+    return floor
+```
+
+# GrPA 3
+
+Note that this `max_heapify` is a workhorse function which you should learn well
+because you're gonna use it very frequently to implement a priority queue.
+
+```python
+def max_heapify(arr, end, current):
+    left = 2 * current + 1
+    right = left + 1
+    largest = current
+
+    if left < end and arr[left] > arr[largest]:
+        largest = left
+    if right < end and arr[right] > arr[largest]:
+        largest = right
+
+    if largest != current:
+        swap(arr, current, largest)
+        max_heapify(arr, end, largest)
+
+def min_max(arr):
+    n = len(arr)
+    for i in reversed(range(n // 2)):
+        max_heapify(arr, n, i)
+```