<p>A <strong>sentence</strong> is a string of single-space separated words where each word consists only of lowercase letters.</p>

<p>A word is <strong>uncommon</strong> if it appears exactly once in one of the sentences, and <strong>does not appear</strong> in the other sentence.</p>

<p>Given two <strong>sentences</strong> <code>s1</code> and <code>s2</code>, return <em>a list of all the <strong>uncommon words</strong></em>. You may return the answer in <strong>any order</strong>.</p>

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

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">s1 = &quot;this apple is sweet&quot;, s2 = &quot;this apple is sour&quot;</span></p>

<p><strong>Output:</strong> <span class="example-io">[&quot;sweet&quot;,&quot;sour&quot;]</span></p>

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

<p>The word <code>&quot;sweet&quot;</code> appears only in <code>s1</code>, while the word <code>&quot;sour&quot;</code> appears only in <code>s2</code>.</p>
</div>

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

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">s1 = &quot;apple apple&quot;, s2 = &quot;banana&quot;</span></p>

<p><strong>Output:</strong> <span class="example-io">[&quot;banana&quot;]</span></p>
</div>

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

<ul>
	<li><code>1 &lt;= s1.length, s2.length &lt;= 200</code></li>
	<li><code>s1</code> and <code>s2</code> consist of lowercase English letters and spaces.</li>
	<li><code>s1</code> and <code>s2</code> do not have leading or trailing spaces.</li>
	<li>All the words in <code>s1</code> and <code>s2</code> are separated by a single space.</li>
</ul>

class Solution {
public:
    vector<string> uncommonFromSentences(string s1, string s2) {
        unordered_map<string,int> mp;
        vector<string> rtn;
        int start = 0, n;
        s1 += ' ';
        n = s1.size();
        for(int i=0;i<n;i++){
            if(s1[i] ==' '){
                string tmp = s1.substr(start,i-start);        
                start = i+1;
                mp[tmp]++;
            }
        }
        s2 += ' ';
        n = s2.size();
        start = 0;
        for(int i=0;i<n;i++){
            if(s2[i] ==' '){
                string tmp = s2.substr(start,i-start);        
                start = i+1;
                mp[tmp]++;
            }
        }
        for(auto s3 : mp){
            if(s3.second == 1){
                rtn.push_back(s3.first);
            }
        }
        return rtn;
    }
};
9100