<p>A transaction is possibly invalid if:</p>

<ul>
	<li>the amount exceeds <code>$1000</code>, or;</li>
	<li>if it occurs within (and including) <code>60</code> minutes of another transaction with the <strong>same name</strong> in a <strong>different city</strong>.</li>
</ul>

<p>You are given an array of strings <code>transaction</code> where <code>transactions[i]</code> consists of comma-separated values representing the name, time (in minutes), amount, and city of the transaction.</p>

<p>Return a list of <code>transactions</code> that are possibly invalid. You may return the answer in <strong>any order</strong>.</p>

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

<pre>
<strong>Input:</strong> transactions = [&quot;alice,20,800,mtv&quot;,&quot;alice,50,100,beijing&quot;]
<strong>Output:</strong> [&quot;alice,20,800,mtv&quot;,&quot;alice,50,100,beijing&quot;]
<strong>Explanation:</strong> The first transaction is invalid because the second transaction occurs within a difference of 60 minutes, have the same name and is in a different city. Similarly the second one is invalid too.</pre>

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

<pre>
<strong>Input:</strong> transactions = [&quot;alice,20,800,mtv&quot;,&quot;alice,50,1200,mtv&quot;]
<strong>Output:</strong> [&quot;alice,50,1200,mtv&quot;]
</pre>

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

<pre>
<strong>Input:</strong> transactions = [&quot;alice,20,800,mtv&quot;,&quot;bob,50,1200,mtv&quot;]
<strong>Output:</strong> [&quot;bob,50,1200,mtv&quot;]
</pre>

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

<ul>
	<li><code>transactions.length &lt;= 1000</code></li>
	<li>Each <code>transactions[i]</code> takes the form <code>&quot;{name},{time},{amount},{city}&quot;</code></li>
	<li>Each <code>{name}</code> and <code>{city}</code> consist of lowercase English letters, and have lengths between <code>1</code> and <code>10</code>.</li>
	<li>Each <code>{time}</code> consist of digits, and represent an integer between <code>0</code> and <code>1000</code>.</li>
	<li>Each <code>{amount}</code> consist of digits, and represent an integer between <code>0</code> and <code>2000</code>.</li>
</ul>

class Solution {
public:
    static bool cmp(vector<string>& a, vector<string>& b) {
        if(stoi(a[0]) <= stoi(b[0])) {
            return true;
        }
        return false;
    }
    vector<string> invalidTransactions(vector<string>& transactions) {
        // store the journey of every person in the same place 
        unordered_map<string, vector<vector<string>>> mp;
        for(auto t : transactions) {
            string temp = "";
            string name = "";
            vector<string> v;
            for(auto i : t) {
                if(i == ',') {
                    if(name.empty()) {
                        name = temp;
                    }
                    else {
                        v.push_back(temp);
                    }
                    temp = "";
                }
                else {
                    temp += i;
                }
            }
            v.push_back(temp);
            mp[name].push_back(v);
        }
        // sort the journey of every person on the basis of time 
        for(auto& t : mp) {
            if(t.second.size() > 1)
                sort(t.second.begin(), t.second.end(), cmp);
        }
        // find invalid transactions
        vector<string> invalid;
        for(auto& t : mp) {
            unordered_set<int> invalidIndexes;
            for(int i = 0; i < t.second.size(); i++) {
                if(stoi(t.second[i][1]) > 1000) { // invalid transaction
                    invalidIndexes.insert(i);
                }
                int j = i + 1;
                while(j < t.second.size() && (stoi(t.second[j][0]) - stoi(t.second[i][0])) <= 60) { // invalid transactions
                    if((t.second[i][2] != t.second[j][2])) {
                        invalidIndexes.insert(i);
                        invalidIndexes.insert(j);
                    }
                    j++;
                }
            }
            for(auto i : invalidIndexes) {
                string str = t.first + ',' + t.second[i][0] + ',' + t.second[i][1] + ',' + t.second[i][2];
                invalid.push_back(str);
            }
        }
        return invalid;
    }
};
22000