198. House Robber

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time: O(n)

space: O(1)

/**
 * @param {number[]} nums
 * @return {number}
 */
var rob = function(nums) {
    if (nums.length === 1) 
        return nums[0];
    
    let first = nums[0];
    let second = Math.max(first, nums[1]);

    for (let i = 2; i < nums.length; i++) {
        const curr = nums[i];

        const max = Math.max(first + curr, second);
        first = second;
        second = max;
    }

    return second;
};

time: O(n)

space: O(n)

/**
 * @param {number[]} nums
 * @return {number}
 */
var rob = function(nums) {

    const sum = new Array(nums.length);
    sum[0] = nums[0];
    sum[1] = Math.max(sum[0], nums[1]);

    for (let i = 2; i < nums.length; i++) {
        const curr = nums[i];

        sum[i] = Math.max(sum[i - 2] + curr, sum[i - 1]);
        sum[i] = Math.max(curr, sum[i]);
    }

    return sum[nums.length - 1];
};