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class Solution {
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  public boolean isRobotBounded(String instructions) {
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    if (instructions.length() == 0) {
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      return true;
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    }
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    Robot bender = new Robot();
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    int[] start = new int[] {0, 0};
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    // 4 represents the max 90 degree turns that can restart initial orientation.
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    for (int i = 0; i < 4; i++) {
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      boolean orientationChanged = bender.performSet(instructions);
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      int[] location = bender.location;
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      if (location[0] == start[0] && location[1] == start[1]) {
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        return true;
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      }
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      // If robot never turns and the first instruction isn't at start, exit.
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      else if (!orientationChanged) {
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        return false;
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      }
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    }
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    return false;
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  }
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}
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class Robot {
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  int[] location;
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  int[] orientation;
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  int[][] orientations;
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  int orientationPos;
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  boolean orientationChangeCheck;
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  Robot() {
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    // Start in center
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    location = new int[] {0, 0};
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    // N, E, S, W
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    orientations = new int[][] {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
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    // Start pointing north
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    orientationPos = 0;
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    orientation = orientations[orientationPos];
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    // Track if robot has turned
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    orientationChangeCheck = false;
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  }
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  public boolean performSet(String orders) {
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    this.orientationChangeCheck = false;
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    for (int i = 0; i < orders.length(); i++) {
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      this.perform(orders.charAt(i));
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    }
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    return this.orientationChangeCheck;
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  }
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  public void perform(char order) {
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    if (order == 'G') {
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      this.go();
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    } else if (order == 'L' || order == 'R') {
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      this.turn(order);
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    } else {
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      // do nothing
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    }
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  }
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  public void turn(char direction) {
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    if (direction == 'L') {
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      this.orientationPos = this.orientationPos == 0 ? 3 : this.orientationPos - 1;
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    } else if (direction == 'R') {
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      this.orientationPos = (this.orientationPos + 1) % 4;
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    }
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    this.orientation = this.orientations[this.orientationPos];
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    this.orientationChangeCheck = true;
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  }
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  public int[] go() {
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    this.location[0] += this.orientation[0];
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    this.location[1] += this.orientation[1];
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    return this.location;
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  }
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}