<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:
    struct Transaction {
        int time;
        int amount;
        string name;
        string city;
        int idx;
    };

    vector<string> invalidTransactions(vector<string>& transactions) {
        unordered_map<string, vector<Transaction>> trans;
        for (int i=0; i<transactions.size(); ++i) {
            stringstream ss(transactions[i]);
            string name;
            string timeStr;
            string amountStr;
            string city;
            getline(ss, name, ',');
            getline(ss, timeStr, ',');
            getline(ss, amountStr, ',');
            getline(ss, city, ',');
            int time = stoi(timeStr);
            int amount = stoi(amountStr);
            Transaction tr = {time, amount, name, city, i};
            trans[name].push_back(tr);
        }
        unordered_set<int> invalid;
        for (auto p : trans) {
            sort(p.second.begin(), p.second.end(), [](Transaction& a, Transaction& b){
                return a.time < b.time;
            });
            int i=0, j=0, k=0;
            unordered_map<string, int> cities;
            int cnt = 0;
            while (i < p.second.size()) {
                int time = p.second[i].time;
                if (p.second[i].amount > 1000)
                    invalid.insert(p.second[i].idx);
                while (j<p.second.size() && p.second[j].time <= time+60) {
                    int temp = cities[p.second[j].city]++;
                    if (temp == 0) ++cnt;
                    if (cnt > 1) {
                        if (k < i) k = i;
                        for (; k<=j; ++k) {
                            invalid.insert(p.second[k].idx);
                        }
                    }
                    ++j;
                }
                int temp = --cities[p.second[i].city];
                if (cities[p.second[i].city] == 0) --cnt;
                ++i;
            }
        }
        vector<string> res;
        for (auto idx : invalid) {
            res.push_back(transactions[idx]);
        }
        return res;
    }
};
20300