codingpineapple

Posted on

LeetCode 1169. Invalid Transactions (javascript solution)

Description:

A transaction is possibly invalid if:

the amount exceeds \$1000, or;
if it occurs within (and including) 60 minutes of another transaction with the same name in a different city.
You are given an array of strings transaction where transactions[i] consists of comma-separated values representing the name, time (in minutes), amount, and city of the transaction.

Return a list of transactions that are possibly invalid. You may return the answer in any order.

Solution:

Time Complexity : O(n^2)
Space Complexity: O(n)

``````const isInvalid = (transaction, map) => {
const [name, time, amount, city] = transaction.split(',')

if (amount > 1000) return true

const prevTrans = map[name]

for (const trans of prevTrans) {
if (city !== trans.city && Math.abs(time - trans.time) <= 60) return true
}

return false
}

const invalidTransactions = transactions => {
const invalid = []
const map = {}

// Sepearate transactions by name
for (const trans of transactions) {
const [name, time, amount, city] = trans.split(',')

// Create a list of transactions under each name
if (name in map) map[name].push({ time, city })
else map[name] = [{ time, city }]
}

// Validate transactions
for (const trans of transactions) {
if (isInvalid(trans, map)) invalid.push(trans)
}

return invalid
};
``````

CJLeverett

I don't get it, I did something almost exactly the same but not sure why it won't pass.

``````function invalidTransactions(transactions) {
const review = {};
const invalidTransactions = [];

for (const t of transactions) {
const [name, time, , city] = t.split(',');

if (name in review) review[name].push({ time, city });
else review[name] = [{ time, city }];
}

for (const transaction of transactions) {
const [name, time, amount, city] = transaction.split(',');
const prevTransactions = review[name];

if (amount > 1000) {
invalidTransactions.push(transaction);
}

for (const prevTransaction of prevTransactions) {
const { time: prevTime, city: prevCity } = prevTransaction;

if (city !== prevCity && Math.abs(time - prevTime) <= 60) {
invalidTransactions.push(transaction);
}
}
}

return Array.from(invalidTransactions);
}
``````