Solutions to past Jane Street puzzles that I've solved.
You can find the puzzle statement for this month here.
This puzzle can be filled by hand rather easily once you figure out what the maximum number appearing on the grid must be. There are \( 17 \) regions so if \( N \) is the maximum number we know that \( N(N+1) \) is divisible by \( 17 \), so either \( N \) or \( N+1 \) must be divisible by \( 17 \). We also know that \( N \geq 33 \) since \( 33 \) is on the grid. Importantly, we can figure out that the upper right pink region containing \( 23 \) must also contain \( 22 \) and \( 24 \), so its sum is bounded from below by \( 23 \cdot 3 = 69 \). This means \( N \) can’t be \( 33 \) or \( 34 \), so it has to be at least \( 50 \), and it turns out it is in fact exactly \( 50 \).
My own visualization of the solution is worse than the one on the solution page over at Jane Street, so you can check that out for a complete solution. Once you know the region sums must all be \( 50 \cdot 51/34 = 25 \cdot 3 = 75 \) it’s very much like solving a sudoku puzzle to fill the numbers in. The final answer turns out to be 14820.