<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> word(const string& text) {
        vector<string> ans;
        string a = "";
        for (int i = 0; i < text.size(); i++) {
            if (text[i] == ',') {
                ans.push_back(a); 
                a = "";
            } else {
                a += text[i];
            }
        }
        ans.push_back(a); // Add the last word
        return ans;
    }
    
    vector<string> invalidTransactions(vector<string>& transactions) {
        vector<string> ans;
        unordered_map<string, vector<vector<string>>> transactionMap;
        
        // Process each transaction and split it into components
        for (int i = 0; i < transactions.size(); i++) {
            vector<string> components = word(transactions[i]);
            transactionMap[components[0]].push_back(components);
        }
        
        // Check for invalid transactions
        for (auto& entry : transactionMap) {
            vector<vector<string>>& transList = entry.second;
            int n = transList.size();
            for (int i = 0; i < n; i++) {
                string name = transList[i][0];
                int time = stoi(transList[i][1]);
                int amount = stoi(transList[i][2]);
                string city = transList[i][3];

                // Check if amount exceeds $1000
                if (amount > 1000) {
                    ans.push_back(name + "," + transList[i][1] + "," + transList[i][2] + "," + city);
                    continue;
                }

                // Check for transactions within 60 minutes in a different city
                for (int j = 0; j < n; j++) {
                    if (i != j) {
                        int otherTime = stoi(transList[j][1]);
                        string otherCity = transList[j][3];
                        if (abs(time - otherTime) <= 60 && city != otherCity) {
                            ans.push_back(name + "," + transList[i][1] + "," + transList[i][2] + "," + city);
                            break;
                        }
                    }
                }
            }
        }
        
        return ans;
    }
};

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