<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> result;
        unordered_map<string, vector<vector<string>>> transactionMap;

        // Step 1: Parse all transactions and group them by name
        for (const string& transaction : transactions) {
            vector<string> parsedTransaction = parseTransaction(transaction);
            transactionMap[parsedTransaction[0]].push_back(parsedTransaction);
        }

        // Step 2: Check for invalid transactions
        for (const string& transaction : transactions) {
            vector<string> parsedTransaction = parseTransaction(transaction);
            string name = parsedTransaction[0];
            int time = stoi(parsedTransaction[1]);
            int amount = stoi(parsedTransaction[2]);
            string city = parsedTransaction[3];

            // Flag to check if the transaction is invalid
            bool isInvalid = false;

            // Check if the amount exceeds 1000
            if (amount > 1000) {
                isInvalid = true;
            }

            // Check for same name transactions within 60 minutes in different cities
            for (const vector<string>& otherTransaction : transactionMap[name]) {
                if (otherTransaction[3] != city && abs(stoi(otherTransaction[1]) - time) <= 60) {
                    isInvalid = true;
                    break;
                }
            }

            // If the transaction is invalid, add it to the result
            if (isInvalid) {
                result.push_back(transaction);
            }
        }

        return result;
    }

private:
    // Helper function to parse a transaction string
    vector<string> parseTransaction(const string& transaction) {
        vector<string> parsedTransaction;
        stringstream ss(transaction);
        string part;
        
        while (getline(ss, part, ',')) {
            parsedTransaction.push_back(part);
        }

        return parsedTransaction;
    }
};

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