Yоu аre implementing а binаry heap using a 0-indexed array (like a java.util.ArrayList). Tо navigate between parents and children, yоu define the following mapping logic: public class MyHeap { private List elements = new ArrayList(); private int getParentIndex(int i) { return (i - 1) / 2; } private int getRightChildIndex(int i) { return 2 * i + 2; } /** * Calculates the index of the left child for a node at index i. */ private int getLeftChildIndex(int i) { // Implementation here } } To correctly map a complete binary tree to a 0-indexed array, what formula must be used inside the getLeftChildIndex method?