Pattern visualizer
Spiral Matrix
A spiral is just four straight walks repeated: right along the top row, down the right column, left along the bottom row, up the left column — then shrink whichever boundary you just finished and repeat on the smaller rectangle inside. Track top/bottom/left/right boundaries; the walk stops once they cross. Animated on: matrix = [[1,2,3],[4,5,6],[7,8,9]] — return all elements in spiral order (shown flattened row-major, index = row*3+col)..
Four shrinking boundaries
time O(rows * cols)space O(1) extrastep 1 / 10
1
[0]2
[1]3
[2]4
[3]5
[4]6
[5]7
[6]8
[7]9
[8]line 4
Start at top-left, heading right. Visit 1 (idx0).
Pseudocode
1FUNCTION spiralOrder(matrix):2 top = 0, bottom = rows - 1, left = 0, right = cols - 13 WHILE top <= bottom and left <= right:4 walk right along row top, then move top one row down5 walk down along column right, then move right one column left6 walk left along row bottom, then move bottom one row up7 walk up along column left, then move left one column right8 RETURN the collected values
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