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Classes › CS 61B › Lectures

Lecture 14: Heaps

A complete binary tree in an array. The parent of k sits at k / 2.

void swim(int k) {
  while (k > 1 && less(k / 2, k)) {
    swap(k, k / 2); k = k / 2;
  }
}

Due this week

PS 5 CS 61B · FriLab 3 CS 61B · TueReading 6 ECON 1 · Thu

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Assignment→ Classes › CS 61B › Assignments

Title: PS 5
Class: CS 61B
Due: Fri · 11:59 PM

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CS 61B › Lectures

Lecture 14: Heaps

A binary heap is a complete binary tree stored in an array.
In a min-heap, every parent is less than or equal to its children.
With the array starting at index 1, the children of k sit at 2k and 2k + 1, and the parent of k sits at k / 2.
Insert puts the new item at the end and swims it up; removing the minimum moves the last item to the top and sinks it down.
Both operations take O(log n) time, because the tree's height is log n.

Quiz me · 1 of 3Flashcards +0

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