Problem Description
You are given an integer array rewardValues
of length n
, representing the values of rewards. Initially, your total reward x
is 0, and all indices are unmarked. You are allowed to perform the following operation any number of times: Choose an unmarked index i
from the range [0, n - 1]
. If rewardValues[i]
is greater than your current total reward x
, then add rewardValues[i]
to x
(i.e., x = x + rewardValues[i]
), and mark the index i
. Return an integer denoting the maximum total reward you can collect by performing the operations optimally.
Key Insights
- The greedy approach is optimal for this problem as we want to maximize the total reward.
- We can only add a reward if it is greater than the current total reward
x
. - Sorting the array helps in efficiently selecting the maximum rewards that can be added without violating the condition.
- After sorting, we can iterate through the rewards and keep adding them to
x
while ensuring the condition is met.
Space and Time Complexity
Time Complexity: O(n log n) - due to sorting the array.
Space Complexity: O(1) - as we are using a constant amount of extra space.
Solution
To solve this problem, we will use a greedy algorithm. First, we sort the rewardValues
array in ascending order. Then, we iterate through the sorted array and maintain a variable x
that tracks the total reward. For each reward in the sorted list, we check if it is greater than x
. If it is, we add it to x
and mark it as included. This ensures that we are always maximizing our total reward by only adding rewards that can be added according to the rules.