A Min Heap is a complete binary tree where every parent is smaller than its children. The minimum element is always at the root, giving O(1) access to the smallest value.
Every node satisfies: parent ≤ children. Stored as an array — node at index i has children at 2i+1 and 2i+2. Parent of i = floor((i-1)/2). This layout gives O(1) parent/child access.