Vector growth 3

Understanding C++ vector capacity and reallocation in this medium-difficulty question

This is a medium-difficulty C++ language-knowledge question that tests your understanding of how standard library vectors manage memory under the hood. It requires you to trace through repeated insertions, explicit reserve calls, and capacity changes to predict exact program output.

To solve problems like this, you need to track the distinction between a vector's size (number of elements) and capacity (allocated storage), understand when and how reallocation occurs, and predict the doubling-growth strategy used by typical standard library implementations. The question rewards careful step-by-step simulation over guessing.

• Vector size vs. capacity semantics
• Reserve and its effect on future allocations
• Reallocation triggers and capacity-doubling strategy
• Interaction between explicit reserve calls and dynamic growth