t = int(input())
for tc in range(t):
n = int(input())
s = input()
mn = 0
mx = 0
cur = 0
for c in s:
if (cur % 2 == 0) == (c == '1'):
cur = cur + 1
else:
cur = cur - 1
mn = min(mn, cur)
mx = max(mx, cur)
print(mx - mn)97. Interleaving String | 543. Diameter of Binary Tree |
124. Binary Tree Maximum Path Sum | 1465. Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts |
501A - Contest | 160A- Twins |
752. Open the Lock | 1535A - Fair Playoff |
1538F - Interesting Function | 1920. Build Array from Permutation |
494. Target Sum | 797. All Paths From Source to Target |
1547B - Alphabetical Strings | 1550A - Find The Array |
118B - Present from Lena | 27A - Next Test |
785. Is Graph Bipartite | 90. Subsets II |
1560A - Dislike of Threes | 36. Valid Sudoku |
557. Reverse Words in a String III | 566. Reshape the Matrix |
167. Two Sum II - Input array is sorted | 387. First Unique Character in a String |
383. Ransom Note | 242. Valid Anagram |
141. Linked List Cycle | 21. Merge Two Sorted Lists |
203. Remove Linked List Elements | 733. Flood Fill |