Watch 10 video solutions for Find Good Days to Rob the Bank, a medium level problem involving Array, Dynamic Programming, Prefix Sum. This walkthrough by Fireship has 1,342,680 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
You and a gang of thieves are planning on robbing a bank. You are given a 0-indexed integer array security, where security[i] is the number of guards on duty on the ith day. The days are numbered starting from 0. You are also given an integer time.
The ith day is a good day to rob the bank if:
time days before and after the ith day,time days before i are non-increasing, andtime days after i are non-decreasing.More formally, this means day i is a good day to rob the bank if and only if security[i - time] >= security[i - time + 1] >= ... >= security[i] <= ... <= security[i + time - 1] <= security[i + time].
Return a list of all days (0-indexed) that are good days to rob the bank. The order that the days are returned in does not matter.
Example 1:
Input: security = [5,3,3,3,5,6,2], time = 2 Output: [2,3] Explanation: On day 2, we have security[0] >= security[1] >= security[2] <= security[3] <= security[4]. On day 3, we have security[1] >= security[2] >= security[3] <= security[4] <= security[5]. No other days satisfy this condition, so days 2 and 3 are the only good days to rob the bank.
Example 2:
Input: security = [1,1,1,1,1], time = 0 Output: [0,1,2,3,4] Explanation: Since time equals 0, every day is a good day to rob the bank, so return every day.
Example 3:
Input: security = [1,2,3,4,5,6], time = 2 Output: [] Explanation: No day has 2 days before it that have a non-increasing number of guards. Thus, no day is a good day to rob the bank, so return an empty list.
Constraints:
1 <= security.length <= 1050 <= security[i], time <= 105