Add 1 or 2

You are given an array $A$ of size $N$ – $[A_1, A_2, \ldots, A_N]$. There will be $B_1 + B_2 + \ldots + B_N$ total events, with exactly $B_i$ events of type $i$. The type $i$ events will happen before the type $i + 1$ events for each $1 \le i \lt N$. In an event of type $X$, you must do **exactly one** of the following: - Add $1$ to $A_X$, or - Add $2$ to $A_Y$ for any $Y \ne X$. Note that the