<p>A robot on an infinite XY-plane starts at point <code>(0, 0)</code> facing north. The robot receives an array of integers <code>commands</code>, which represents a sequence of moves that it needs to execute. There are only three possible types of instructions the robot can receive:</p>

<ul>
	<li><code>-2</code>: Turn left <code>90</code> degrees.</li>
	<li><code>-1</code>: Turn right <code>90</code> degrees.</li>
	<li><code>1 &lt;= k &lt;= 9</code>: Move forward <code>k</code> units, one unit at a time.</li>
</ul>

<p>Some of the grid squares are <code>obstacles</code>. The <code>i<sup>th</sup></code> obstacle is at grid point <code>obstacles[i] = (x<sub>i</sub>, y<sub>i</sub>)</code>. If the robot runs into an obstacle, it will stay in its current location (on the block adjacent to the obstacle) and move onto the next command.</p>

<p>Return the <strong>maximum squared Euclidean distance</strong> that the robot reaches at any point in its path (i.e. if the distance is <code>5</code>, return <code>25</code>).</p>

<p><strong>Note:</strong></p>

<ul>
	<li>There can be an obstacle at <code>(0, 0)</code>. If this happens, the robot will ignore the obstacle until it has moved off the origin. However, it will be unable to return to <code>(0, 0)</code> due to the obstacle.</li>
	<li>North means +Y direction.</li>
	<li>East means +X direction.</li>
	<li>South means -Y direction.</li>
	<li>West means -X direction.</li>
</ul>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">commands = [4,-1,3], obstacles = []</span></p>

<p><strong>Output:</strong> <span class="example-io">25</span></p>

<p><strong>Explanation: </strong></p>

<p>The robot starts at <code>(0, 0)</code>:</p>

<ol>
	<li>Move north 4 units to <code>(0, 4)</code>.</li>
	<li>Turn right.</li>
	<li>Move east 3 units to <code>(3, 4)</code>.</li>
</ol>

<p>The furthest point the robot ever gets from the origin is <code>(3, 4)</code>, which squared is <code>3<sup>2</sup> + 4<sup>2 </sup>= 25</code> units away.</p>
</div>

<p><strong class="example">Example 2:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">commands = [4,-1,4,-2,4], obstacles = [[2,4]]</span></p>

<p><strong>Output:</strong> <span class="example-io">65</span></p>

<p><strong>Explanation:</strong></p>

<p>The robot starts at <code>(0, 0)</code>:</p>

<ol>
	<li>Move north 4 units to <code>(0, 4)</code>.</li>
	<li>Turn right.</li>
	<li>Move east 1 unit and get blocked by the obstacle at <code>(2, 4)</code>, robot is at <code>(1, 4)</code>.</li>
	<li>Turn left.</li>
	<li>Move north 4 units to <code>(1, 8)</code>.</li>
</ol>

<p>The furthest point the robot ever gets from the origin is <code>(1, 8)</code>, which squared is <code>1<sup>2</sup> + 8<sup>2</sup> = 65</code> units away.</p>
</div>

<p><strong class="example">Example 3:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">commands = [6,-1,-1,6], obstacles = [[0,0]]</span></p>

<p><strong>Output:</strong> <span class="example-io">36</span></p>

<p><strong>Explanation:</strong></p>

<p>The robot starts at <code>(0, 0)</code>:</p>

<ol>
	<li>Move north 6 units to <code>(0, 6)</code>.</li>
	<li>Turn right.</li>
	<li>Turn right.</li>
	<li>Move south 5 units and get blocked by the obstacle at <code>(0,0)</code>, robot is at <code>(0, 1)</code>.</li>
</ol>

<p>The furthest point the robot ever gets from the origin is <code>(0, 6)</code>, which squared is <code>6<sup>2</sup> = 36</code> units away.</p>
</div>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= commands.length &lt;= 10<sup>4</sup></code></li>
	<li><code>commands[i]</code> is either <code>-2</code>, <code>-1</code>, or an integer in the range <code>[1, 9]</code>.</li>
	<li><code>0 &lt;= obstacles.length &lt;= 10<sup>4</sup></code></li>
	<li><code>-3 * 10<sup>4</sup> &lt;= x<sub>i</sub>, y<sub>i</sub> &lt;= 3 * 10<sup>4</sup></code></li>
	<li>The answer is guaranteed to be less than <code>2<sup>31</sup></code>.</li>
</ul>

int init = [](){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    return 0;
}();

class Solution {
    int ans = 0;
    unordered_map<int, vector<int>> umap1;

public:
    int robotSim(vector<int>& commands, vector<vector<int>>& obstacles) {
        // int m=obstacles.size();
        // int n=obstacles[0].size();
        vector<int> commandsNew;

        for (int i = 0; i < commands.size(); i++) {
            if (commands[i] == -1 || commands[i] == -2) {
                // skip
                commandsNew.push_back(commands[i]);
            } else {
                for (int j = 0; j < commands[i]; j++) {
                    commandsNew.push_back(1);
                }
            }
        }
        vector<vector<int>> grid;
        for (int i = 0; i < obstacles.size(); i++) {

            umap1[obstacles[i][0]].push_back(obstacles[i][1]);
        }

        compute(commandsNew, grid, 0, 0, 0, 1); //+1,-1,-2,+2
        return ans;
    }
    void compute(const vector<int>& commands, const vector<vector<int>>& grid,
                 int x, int y, int cmd, int dir) {

        ans = max(ans, x * x + y * y);
        if (cmd == commands.size()) {

            return;
        } else {
            if (commands[cmd] == -1 && dir == 1) { // right
                compute(commands, grid, x, y, cmd + 1, 2);
            } else if (commands[cmd] == -1 && dir == -1) { // right
                compute(commands, grid, x, y, cmd + 1, -2);
            } else if (commands[cmd] == -2 && dir == 1) { // right
                compute(commands, grid, x, y, cmd + 1, -2);
            } else if (commands[cmd] == -2 && dir == -1) { // left
                compute(commands, grid, x, y, cmd + 1, 2);
            } else if (commands[cmd] == -1 && dir == 2) { // right
                compute(commands, grid, x, y, cmd + 1, -1);
            } else if (commands[cmd] == -1 && dir == -2) { // right
                compute(commands, grid, x, y, cmd + 1, 1);
            } else if (commands[cmd] == -2 && dir == 2) { // left
                compute(commands, grid, x, y, cmd + 1, 1);
            } else if (commands[cmd] == -2 && dir == -2) { // left
                compute(commands, grid, x, y, cmd + 1, -1);
            } else if (dir == -2) {
                // left
                if (umap1.find(x - 1) != umap1.end()) {
                    vector<int>& vec =
                        umap1[x -
                              1]; // Access the vector associated with the key

                    if (find(vec.begin(), vec.end(), y) != vec.end()) {
                        compute(commands, grid, x, y, cmd + 1, dir);
                    } else {
                        compute(commands, grid, x - 1, y, cmd + 1, dir);
                    }
                    // skip

                } else {
                    compute(commands, grid, x - 1, y, cmd + 1, dir);
                }

            } else if (dir == 2) {
                if (umap1.find(x + 1) != umap1.end()) {
                    vector<int>& vec =
                        umap1[x +
                              1]; // Access the vector associated with the key

                    if (find(vec.begin(), vec.end(), y) != vec.end()) {
                        compute(commands, grid, x, y, cmd + 1, dir);
                    } else {
                        compute(commands, grid, x + 1, y, cmd + 1, dir);
                    }
                    // skip

                } else {
                    compute(commands, grid, x + 1, y, cmd + 1, dir);
                }

            } else if (dir == 1) {
                if (umap1.find(x) != umap1.end()) {
                    vector<int>& vec =
                        umap1[x]; // Access the vector associated with the key

                    if (find(vec.begin(), vec.end(), y + 1) != vec.end()) {
                        compute(commands, grid, x, y, cmd + 1, dir);
                    } else {
                        compute(commands, grid, x, y + 1, cmd + 1, dir);
                    }
                    // skip

                } else {
                    compute(commands, grid, x, y + 1, cmd + 1, dir);
                }

            } else if (dir == -1) {
                if (umap1.find(x) != umap1.end()) {

                    vector<int>& vec =
                        umap1[x]; // Access the vector associated with the key

                    if (find(vec.begin(), vec.end(), y - 1) != vec.end()) {

                        compute(commands, grid, x, y, cmd + 1, dir);
                    } else {
                        compute(commands, grid, x, y - 1, cmd + 1, dir);
                    }
                    // skip

                } else {
                    compute(commands, grid, x, y - 1, cmd + 1, dir);
                }
            }
        }
    }
};
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