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$ curl repovive.com/roadmaps/google-interview-prep-v2/coding-patterns-ii-trees-graphs-dynamic-programming/lc-1041-robot-bounded-in-circle-implementation

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$ curl repovive.com/roadmaps/google-interview-prep-v2/coding-patterns-ii-trees-graphs-dynamic-programming/lc-1041-robot-bounded-in-circle-implementation

Repovive

LeetCode 1041 Robot Bounded In Circle - Implementation - Coding Patterns II: Trees, Graphs & Dynamic Programming | Google Interview Prep | Repovive

Repovive.

Google Interview Prep6 sections · 128 units7h total

Open in Course

LeetCode 1041 Robot Bounded In Circle - Implementation

The code

Simulate one pass through the instructions. Check if position is origin or direction changed.

function isRobotBounded(instructions):
    dx = [0, 1, 0, -1]
    dy = [1, 0, -1, 0]
    x = 0
    y = 0
    dir = 0
    for ch in instructions:
        if ch == 'G':
            x += dx[dir]
            y += dy[dir]
        elif ch == 'L':
            dir = (dir + 3) % 4
        elif ch == 'R':
            dir = (dir + 1) % 4
    return (x == 0 and y == 0) or dir != 0

$O(n)$ time, $O(1)$ space.