Question 13
Jin wants a stone bridge home. Pressing a numbered button toggles every cell in that column: a stone disappears and an empty cell gains a stone. A lettered button similarly toggles an entire row. Jin can move between horizontally or vertically adjacent stones, never diagonally.
Hải ly marks Jin beside cell a 5, and Nhà marks home below e 1. What is the minimum number of button presses needed?
Hải ly marks Jin beside cell a 5, and Nhà marks home below e 1. What is the minimum number of button presses needed?