<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>

struct Transaction {
    string name;
    int time;
    int amount;
    string city;
};

class Solution {
public:
    vector<string> invalidTransactions(vector<string>& transactions) {
        vector<Transaction> parsedTransactions;
    vector<string> result;
    
    for (string& trans : transactions) {
        stringstream ss(trans);
        string token;
        vector<string> tokens;
        while (getline(ss, token, ',')) {
            tokens.push_back(token);
        }
        
        Transaction t = {tokens[0], stoi(tokens[1]), stoi(tokens[2]), tokens[3]};
        parsedTransactions.push_back(t);
    }
    
    unordered_map<string, vector<Transaction>> transactionsByName;
    for (const Transaction& t : parsedTransactions) {
        transactionsByName[t.name].push_back(t);
    }
    
    for (const Transaction& t : parsedTransactions) {
        if (t.amount > 1000) {
            result.push_back(t.name + "," + to_string(t.time) + "," + to_string(t.amount) + "," + t.city);
        } else {
            for (const Transaction& other : transactionsByName[t.name]) {
                if (t.city != other.city && abs(t.time - other.time) <= 60) {
                    result.push_back(t.name + "," + to_string(t.time) + "," + to_string(t.amount) + "," + t.city);
                    break;
                }
            }
        }
    }
    
    return result;
    }
};
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