blind-75-leetcode-questions/22--house-robber.java at main · mdabarik/blind-75-leetcode-questions · GitHub

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class Solution {
    public int rob(int[] nums) {
        if (nums.length == 1) return nums[0];
        int[] dp = new int[nums.length + 1];
        dp[0] = nums[0];
        dp[1] = Math.max(nums[0], nums[1]);
        for (int i = 2; i < nums.length; i++) {
            int rob = nums[i] + dp[i - 2];
            int notRob = dp[i - 1];
            dp[i] = Math.max(rob, notRob);
        }
        return dp[nums.length - 1];
    }
} // TC: O(n), SC: O(n)

class Solution {
    public int rob(int[] nums) {
        if (nums.length == 1) return nums[0];
        int prev1 = nums[0];
        int prev2 = Math.max(nums[0], nums[1]);
        for (int i = 2; i < nums.length; i++) {
            int curr = Math.max(nums[i] + prev1, prev2);
            prev1 = prev2;
            prev2 = curr;
        }
        return prev2;
    }
} // TC: O(n), SC: O(1)