Binary Search Lab — hunt for YOUR number — Visualize

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🧪 Your experiment — type any numbers, pick a target (present or missing!), and hunt for it

6 numbers (1–99). We will SORT them first — binary search refuses to work on unsorted data, and that rule is half the lesson.

nums =find:

Binary Search Lab — hunt for YOUR number

Type six numbers and a target — then watch half the possibilities die with every single comparison.

💡

THE BIG IDEA

Binary search is the interview classic: instead of checking boxes one by one, look at the middle, throw away the half that cannot contain your target, and repeat. Type your own numbers and pick your own target — including one that is NOT there, because watching low and high squeeze shut on nothing is the part everyone fumbles in interviews. One rule first: we sort your numbers before starting. Binary search demands it.

Move your mouse over any line to see what it does. Hover a loop line and it plays through every repeat. Or press ▶ Play to watch the whole thing. On a phone, tap the arrows.

1nums = [4, 9, 15, 23, 38, 57]
2target = 15
3low, high, found = 0, 5, -1
4while low <= high and found == -1:
5    mid = (low + high) // 2
6    if nums[mid] == target:
7        found = mid
8    elif nums[mid] < target:
9        low = mid + 1
10    else:
11        high = mid - 1
12print("found at index", found)