{ "data": { "question": { "questionId": "1324", "questionFrontendId": "1706", "boundTopicId": null, "title": "Where Will the Ball Fall", "titleSlug": "where-will-the-ball-fall", "content": "
You have a 2-D grid
of size m x n
representing a box, and you have n
balls. The box is open on the top and bottom sides.
Each cell in the box has a diagonal board spanning two corners of the cell that can redirect a ball to the right or to the left.
\n\n1
.-1
.We drop one ball at the top of each column of the box. Each ball can get stuck in the box or fall out of the bottom. A ball gets stuck if it hits a "V" shaped pattern between two boards or if a board redirects the ball into either wall of the box.
\n\nReturn an array answer
of size n
where answer[i]
is the column that the ball falls out of at the bottom after dropping the ball from the ith
column at the top, or -1
if the ball gets stuck in the box.
\n
Example 1:
\n\n\n\n
\nInput: grid = [[1,1,1,-1,-1],[1,1,1,-1,-1],[-1,-1,-1,1,1],[1,1,1,1,-1],[-1,-1,-1,-1,-1]]\nOutput: [1,-1,-1,-1,-1]\nExplanation: This example is shown in the photo.\nBall b0 is dropped at column 0 and falls out of the box at column 1.\nBall b1 is dropped at column 1 and will get stuck in the box between column 2 and 3 and row 1.\nBall b2 is dropped at column 2 and will get stuck on the box between column 2 and 3 and row 0.\nBall b3 is dropped at column 3 and will get stuck on the box between column 2 and 3 and row 0.\nBall b4 is dropped at column 4 and will get stuck on the box between column 2 and 3 and row 1.\n\n\n
Example 2:
\n\n\nInput: grid = [[-1]]\nOutput: [-1]\nExplanation: The ball gets stuck against the left wall.\n\n\n
Example 3:
\n\n\nInput: grid = [[1,1,1,1,1,1],[-1,-1,-1,-1,-1,-1],[1,1,1,1,1,1],[-1,-1,-1,-1,-1,-1]]\nOutput: [0,1,2,3,4,-1]\n\n\n
\n
Constraints:
\n\nm == grid.length
n == grid[i].length
1 <= m, n <= 100
grid[i][j]
is 1
or -1
.Compiled with clang 11
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Your code is compiled with level two optimization (-O2
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Most standard library headers are already included automatically for your convenience.
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