<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:
    vector<string> invalidTransactions(vector<string>& transactions) {
        vector<string> ans;
        unordered_map<string, vector<vector<string>>> transMap;  // Map to store transactions by name

        // Parse transactions and store them in a map by name
        for (const string& transaction : transactions) {
            stringstream ss(transaction);
            string name, time, amount, city;
            getline(ss, name, ',');
            getline(ss, time, ',');
            getline(ss, amount, ',');
            getline(ss, city, ',');

            // Store each transaction details as {time, amount, city}
            transMap[name].push_back({time, amount, city, transaction});
        }

        // Check for invalid transactions
        for (const auto& [name, transList] : transMap) {
            for (int i = 0; i < transList.size(); i++) {
                int time1 = stoi(transList[i][0]);
                int amount1 = stoi(transList[i][1]);
                string city1 = transList[i][2];

                // If amount > 1000, it's invalid
                if (amount1 > 1000) {
                    ans.push_back(transList[i][3]);
                    continue;
                }

                // Check for invalid transactions due to time and city differences
                bool invalid = false;
                for (int j = 0; j < transList.size(); j++) {
                    if (i == j) continue;  // Skip the same transaction
                    int time2 = stoi(transList[j][0]);
                    string city2 = transList[j][2];

                    if (abs(time1 - time2) <= 60 && city1 != city2) {
                        invalid = true;
                        break;
                    }
                }

                if (invalid) {
                    ans.push_back(transList[i][3]);
                }
            }
        }

        return ans;
    }
};
18300