<p>There is an integer array <code>nums</code> that consists of <code>n</code> <strong>unique </strong>elements, but you have forgotten it. However, you do remember every pair of adjacent elements in <code>nums</code>.</p>

<p>You are given a 2D integer array <code>adjacentPairs</code> of size <code>n - 1</code> where each <code>adjacentPairs[i] = [u<sub>i</sub>, v<sub>i</sub>]</code> indicates that the elements <code>u<sub>i</sub></code> and <code>v<sub>i</sub></code> are adjacent in <code>nums</code>.</p>

<p>It is guaranteed that every adjacent pair of elements <code>nums[i]</code> and <code>nums[i+1]</code> will exist in <code>adjacentPairs</code>, either as <code>[nums[i], nums[i+1]]</code> or <code>[nums[i+1], nums[i]]</code>. The pairs can appear <strong>in any order</strong>.</p>

<p>Return <em>the original array </em><code>nums</code><em>. If there are multiple solutions, return <strong>any of them</strong></em>.</p>

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

<pre>
<strong>Input:</strong> adjacentPairs = [[2,1],[3,4],[3,2]]
<strong>Output:</strong> [1,2,3,4]
<strong>Explanation:</strong> This array has all its adjacent pairs in adjacentPairs.
Notice that adjacentPairs[i] may not be in left-to-right order.
</pre>

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

<pre>
<strong>Input:</strong> adjacentPairs = [[4,-2],[1,4],[-3,1]]
<strong>Output:</strong> [-2,4,1,-3]
<strong>Explanation:</strong> There can be negative numbers.
Another solution is [-3,1,4,-2], which would also be accepted.
</pre>

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

<pre>
<strong>Input:</strong> adjacentPairs = [[100000,-100000]]
<strong>Output:</strong> [100000,-100000]
</pre>

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

<ul>
	<li><code>nums.length == n</code></li>
	<li><code>adjacentPairs.length == n - 1</code></li>
	<li><code>adjacentPairs[i].length == 2</code></li>
	<li><code>2 &lt;= n &lt;= 10<sup>5</sup></code></li>
	<li><code>-10<sup>5</sup> &lt;= nums[i], u<sub>i</sub>, v<sub>i</sub> &lt;= 10<sup>5</sup></code></li>
	<li>There exists some <code>nums</code> that has <code>adjacentPairs</code> as its pairs.</li>
</ul>

class Solution {
public:
   void dfs(vector<int>&res,map<int,pair<vector<int>,bool>>&m1,int item){
	m1[item].second=true;
	res.push_back(item);
	for(int i=0; i<m1[item].first.size(); i++){
		int key=m1[item].first[i];
		if(!m1[key].second){
			dfs(res,m1,key);
		}
	}
}
vector<int> restoreArray(vector<vector<int>>& adjacentPairs) {  // [[2,1],[3,4],[3,2]]
vector<int>res;
        map<int,pair<vector<int>,bool>>m1;
        for(int i=0; i<adjacentPairs.size();i++){
        	m1[adjacentPairs[i][0]].first.push_back(adjacentPairs[i][1]);
        	m1[adjacentPairs[i][0]].second=false;
        	m1[adjacentPairs[i][1]].first.push_back(adjacentPairs[i][0]);
        	m1[adjacentPairs[i][1]].second=false;
		}
		for(int i=0 ;i<adjacentPairs.size(); i++){
			if(m1[adjacentPairs[i][0]].first.size()==1){
				int item=adjacentPairs[i][0];
				dfs(res,m1,item);
				break;
			}
			if(m1[adjacentPairs[i][1]].first.size()==1){
				int item=adjacentPairs[i][1];
				dfs(res,m1,item);
				break;
			}
		}
		return res;
    }
};
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