Okay, here's a challenge.↵
↵
The code below is supposed to find the **smallest integer `x` for which `check(x)` returns `false`**, assuming `check(x)` is `true` for all smaller values and `false` for all larger values.↵
↵
It compiles, and the logic looks pretty normal.↵
↵
```cpp↵
int l = -10, r = 10;↵
↵
while (l < r) {↵
int mid = (l + r) / 2;↵
↵
if (check(mid)) {↵
l = mid + 1;↵
}↵
else {↵
r = mid;↵
}↵
}↵
```↵
↵
Here, `check(x)` returns:↵
- `true` if `x` is smaller than the target.↵
- `false` if `x` is greater than or equal to the target.↵
↵
**Find a valid target for which this code gets stuck or fails.**↵
↵
Rules:↵
- Give the smallest counterexample you can find.↵
- Explain why the code fails.↵
- Bonus: Fix it without changing the overall approach.↵
↵
Try to find the bug before opening the comments.↵
↵
Let's see who catches it first.
↵
The code below is supposed to find the **smallest integer `x` for which `check(x)` returns `false`**, assuming `check(x)` is `true` for all smaller values and `false` for all larger values.↵
↵
It compiles, and the logic looks pretty normal.↵
↵
```cpp↵
int l = -10, r = 10;↵
↵
while (l < r) {↵
int mid = (l + r) / 2;↵
↵
if (check(mid)) {↵
l = mid + 1;↵
}↵
else {↵
r = mid;↵
}↵
}↵
```↵
↵
Here, `check(x)` returns:↵
- `true` if `x` is smaller than the target.↵
- `false` if `x` is greater than or equal to the target.↵
↵
**Find a valid target for which this code gets stuck or fails.**↵
↵
Rules:↵
- Give the smallest counterexample you can find.↵
- Explain why the code fails.↵
- Bonus: Fix it without changing the overall approach.↵
↵
Try to find the bug before opening the comments.↵
↵
Let's see who catches it first.
