198. House Robber

problem

198. House Robber

 solution1:

code

class Solution {
public:
    int rob(vector<int>& nums) {
        int pre = 0;
        int cur = 0;
        for(int i=0; i<nums.size(); i++)
        {
            int tmp = max(pre+nums[i], cur);
            pre = cur;
            cur = tmp;
        }
        return cur;
    }
};

solution2:

M(k) = money at the kth house
P(0) = 0
P(1) = M(1)
P(k) = max(P(k−2) + M(k), P(k−1))

code

class Solution {
public:
    int rob(vector<int>& nums) {
        if(nums.size()==0) return 0;
        if(nums.size()==1) return nums[0];
        if(nums.size()==2) return max(nums[0], nums[1]);
        vector<int> f(nums.size(), 0);
        f[0] = nums[0];
        f[1] = max(nums[0], nums[1]);
        for(int i=2; i<nums.size(); i++)
        {
            f[i] = max(f[i-2]+nums[i], f[i-1]);
        }
        return f[nums.size()-1];
    }
};

1. Leetcode_House Robber;