<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>

#include <ranges>
class Solution {
public:
vector<string> invalidTransactions(vector<string>& transactions) {
    struct Transaction {
        string name;
        int time;
        int amount;
        string city;
        string original;
        int index = 0;
    };
    
    vector<Transaction> parsedTransactions;
    
    // Parse the transactions
    int index = 0;
    for (const string& transaction : transactions) {
        stringstream ss(transaction);
        string name, city, token;
        int time, amount;
        
        getline(ss, name, ',');
        getline(ss, token, ',');
        time = stoi(token);
        getline(ss, token, ',');
        amount = stoi(token);
        getline(ss, city, ',');
        parsedTransactions.push_back({name, time, amount, city, transaction, index});
        index++;
    }
    
    unordered_set<int> invalid;
    unordered_map<string, vector<Transaction>> transactionsByName;
    
    // Group transactions by name
    for (const auto& t : parsedTransactions) {
        transactionsByName[t.name].push_back(t);
    }
    
    // Check for invalid transactions
    for (const auto& [name, trans] : transactionsByName) {
        int n = trans.size();
        
        for (int i = 0; i < n; ++i) {
            const auto& t1 = trans[i];
            
            // Condition 1: Amount exceeds $1000
            if (t1.amount > 1000) {
                invalid.insert(t1.index);
            }
            
            // Condition 2: Transaction occurs within 60 minutes in a different city
            for (int j = 0; j < n; ++j) {
                if (i != j) {
                    const auto& t2 = trans[j];
                    if (abs(t1.time - t2.time) <= 60 && t1.city != t2.city) {
                        invalid.insert(t1.index);
                        invalid.insert(t2.index);
                    }
                }
            }
        }
    }
    vector<string> result;
    for(const auto v : invalid)
    {
        result.push_back(transactions[v]);
    }
    return result;
}
};
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