The answer
When you delete an element, the elements to its right shift left. If you iterate left-to-right, you skip elements. Iterating backwards avoids this shifting index bug.
Iterating Backwards: A Common Interview Pattern
Why is reverse iteration useful for deletion?
More FAQs in Iterating Backwards: A Common Interview Pattern
Initialize the counter to the last index (length - 1), set the condition to run while the counter is greater than or equal to 0, and use decrement (i--).
No, traversing an array from right to left takes the exact same O(N) time and hardware cycles as traversing it from left to right.
It is a classic problem where two sorted arrays are merged in-place into the first array by iterating backwards from the largest elements to the smallest.
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