213. 打家劫舍 II

213. 打家劫舍 II

var rob = function(nums) {
    if (!Array.isArray(nums) || nums.some(isNaN)) {
        throw new Error("Invalid input: nums must be an array of numbers");
    }

    const n = nums.length;
    if (n === 0) return 0;
    if (n === 1) return nums[0];

    function robHelper(arr) {
        let prev = 0, curr = 0;
        for (let num of arr) {
            let temp = Math.max(curr, prev + num);
            prev = curr;
            curr = temp;
        }
        return curr;
    }

    // Case 1: Do not rob the first house
    let case1 = robHelper(nums.slice(1));
    // Case 2: Do not rob the last house
    let case2 = robHelper(nums.slice(0, n - 1));

    return Math.max(case1, case2);
};

var rob = function(nums) {
    if (nums.length === 0) return 0;
    if (nums.length === 1) return nums[0];
    if (nums.length === 2) return Math.max(nums[0], nums[1]);

    let prev1 = 0,curr1=0;
    let prev2 = 0,curr2=0;
    
    for (let i = 1; i < nums.length; i++) {
        let current = Math.max(prev1, curr1 + nums[i]);
        curr1=prev1
        prev1=current
    }
    for (let i = 0; i < nums.length-1; i++) {
        let current = Math.max(prev2, curr2 + nums[i]);
        curr2=prev2
        prev2=current
    }
    return Math.max(prev1, prev2);
};

let nums = [1,2,3]
console.log(rob(nums))

inner loop

out loop v