HouseRobber.java

public int rob(int[] num) {
    if (num == null || num.length == 0) {
        return 0;
    }

    int n = num.length;
    int[] lookup = new int[n + 1]; // DP array size normally larger than 1
    lookup[0] = 0;
    lookup[1] = num[0];

    for (int i = 2; i <= n; i++) {
        lookup[i] = Math.max(lookup[i - 1], lookup[i - 2] + num[i - 1]);
    }

    return lookup[n];
}