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var findBall = function (grid) {
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  let m = grid.length,
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    n = grid[0].length,
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    ans = [];
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  for (let start = 0; start < n; start++) {
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    // Iterate through the different starting conditions
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    let j = start;
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    for (let i = 0; i < m; i++) {
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      // Then iterate downward from grid[i][j]
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      let dir = grid[i][j]; // Compare the direction of the current cell to the direction
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      if (dir === grid[i][j + dir])
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        j += dir; //   of the cell on the slant side and move that way if matched
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      else (i = m), (j = -1); // Otherwise jump to the loop's end and set j to the fail value
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    }
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    ans[start] = j; // Update the answer
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  }
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  return ans; // Return the completed answer
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};