Richest Customer Wealth

1. Define the problem

You are given an m x n integer grid accounts where accounts_i[j] is the amount of money the i-th customer has in the j-th bank. Return the wealth that the richest customer has, where a customer wealth is the sum of all their bank accounts . Sum each row, then track the maximum row sum seen so far as you go.

Constraints

m == accounts.length
n == accounts_i.length
1 ≤ m, n ≤ 50
1 ≤ accounts_i[j] ≤ 100

Example

Inputaccounts = [[1, 2, 3], [3, 2, 1]]

Output6

Explanation Customer 0 has 1+2+3=6, customer 1 has 3+2+1=6, so the richest wealth is 6.

2. Visualize the solution

Sum each customer row, track the largest total

row06

row1?

Statusinit

Customer 0: [1, 2, 3] sums to 6. maxWealth=6.

What happens in this step

row 0 = [1, 2, 3]
sum = 1 + 2 + 3 = 6
maxWealth = 6

Step 1 of 3

Steps to visualize

For each customer (each row), add up every bank balance in that row.
Compare that row sum against the largest sum found so far.
Keep the larger of the two as the new maximum.
After checking every customer, the maximum is the richest wealth.

3. Walk through the code

Walk through the code

Same walkthrough, now with the code. Press Next to move one step and watch which lines run.

Sum each customer row, track the largest total

row06

row1?

Statusinit

Customer 0: [1, 2, 3] sums to 6. maxWealth=6.

What happens in this step

row 0 = [1, 2, 3]
sum = 1 + 2 + 3 = 6
maxWealth = 6

Step 1 of 3

4. Solution

Solution

solution.tsTypeScript

function maximumWealth(accounts) {
  let maxWealth = 0;

  for (const row of accounts) {
    let sum = 0;
    for (const balance of row) {
      sum += balance;
    }
    maxWealth = Math.max(maxWealth, sum);
  }

  return maxWealth;
}

Time: O(m * n)
Space: O(1)

5. Test cases

Test cases

Input	Expected	Covers
`accounts = [[1, 2, 3], [3, 2, 1]]`	`6`	example from the docstring
`accounts = [[1, 5], [7, 3], [3, 5]]`	`10`	one customer clearly richer than the others
`accounts = [[2, 8, 7]]`	`17`	smallest valid input, a single customer
`accounts = [[5], [10], [3]]`	`10`	each customer has only one bank account
`accounts = [[4, 4], [4, 4]]`	`8`	every customer has identical wealth
`accounts = [[100]]`	`100`	smallest possible grid, one customer with one bank

Richest Customer Wealth