codeforces#P1705B. Mark the Dust Sweeper
Mark the Dust Sweeper
Description
Mark is cleaning a row of $n$ rooms. The $i$-th room has a nonnegative dust level $a_i$. He has a magical cleaning machine that can do the following three-step operation.
- Select two indices $i<j$ such that the dust levels $a_i$, $a_{i+1}$, $\dots$, $a_{j-1}$ are all strictly greater than $0$.
- Set $a_i$ to $a_i-1$.
- Set $a_j$ to $a_j+1$.
The first line contains a single integer $t$ ($1\leq t\leq 10^4$) — the number of test cases.
The first line of each test case contains a single integer $n$ ($2\leq n\leq 2\cdot 10^5$) — the number of rooms.
The second line of each test case contains $n$ integers $a_1$, $a_2$, ..., $a_n$ ($0\leq a_i\leq 10^9$) — the dust level of each room.
It is guaranteed that the sum of $n$ across all test cases does not exceed $2\cdot 10^5$.
For each test case, print a line containing a single integer — the minimum number of operations. It can be proven that there is a sequence of operations that meets the goal.
Input
The first line contains a single integer $t$ ($1\leq t\leq 10^4$) — the number of test cases.
The first line of each test case contains a single integer $n$ ($2\leq n\leq 2\cdot 10^5$) — the number of rooms.
The second line of each test case contains $n$ integers $a_1$, $a_2$, ..., $a_n$ ($0\leq a_i\leq 10^9$) — the dust level of each room.
It is guaranteed that the sum of $n$ across all test cases does not exceed $2\cdot 10^5$.
Output
For each test case, print a line containing a single integer — the minimum number of operations. It can be proven that there is a sequence of operations that meets the goal.
Samples
4
3
2 0 0
5
0 2 0 2 0
6
2 0 3 0 4 6
4
0 0 0 10
3
5
11
0
Note
In the first case, one possible sequence of operations is as follows.
- Choose $i=1$ and $j=2$, yielding the array $[1,1,0]$.
- Choose $i=1$ and $j=3$, yielding the array $[0,1,1]$.
- Choose $i=2$ and $j=3$, yielding the array $[0,0,2]$.
In the second case, one possible sequence of operations is as follows.
- Choose $i=4$ and $j=5$, yielding the array $[0,2,0,1,1]$.
- Choose $i=2$ and $j=3$, yielding the array $[0,1,1,1,1]$.
- Choose $i=2$ and $j=5$, yielding the array $[0,0,1,1,2]$.
- Choose $i=3$ and $j=5$, yielding the array $[0,0,0,1,3]$.
- Choose $i=4$ and $j=5$, yielding the array $[0,0,0,0,4]$.
In the last case, the array already satisfies the condition.