LeetCode 337. House Robber III 动态演示

每个节点是个房间，数值代表钱。小偷偷里面的钱，不能偷连续的房间，至少要隔一个。问最多能偷多少钱

TreeNode* cur

mp[{cur, true}]表示以cur为根的树，最多能偷的钱

mp[{cur, false}]表示以cur为根的树，不偷cur节点的钱，最多能偷的钱

可以看出有下面的关系

mp[{node, false}] = mp[{node->left,true}] + mp[{node->right,true}]
mp[{node, true}] = max(node->val + mp[{node->left,false}] + mp[{node->right,false}], mp[{node, false}])

 

class Solution {
public:
    void helper(TreeNode* node, map<pair<TreeNode*, bool>,int>& mp){
        if(!node){
            return;        
        }
        //a(node)
        //lk("root",node)
        
        helper(node->left, mp);
        helper(node->right, mp);
        mp[{node, false}] = mp[{node->left,true}] +  mp[{node->right,true}];
        mp[{node, true}] = max(node->val + mp[{node->left,false}] +  mp[{node->right,false}], 
                               mp[{node, false}]);
        //dsp
        
    }
    
    int rob(TreeNode* root) {        
        map<pair<TreeNode*, bool>,int> mp;  
       //amap(mp, pair<TreeNode*, bool>,int)
        //ahd(root)
        mp[{NULL, true}]=0;
        mp[{NULL, false}]=0;
        helper(root, mp);
        return max(mp[{root, false}], mp[{root, true}]);
    }
};

动态演示 http://simpledsp.com/FS/Html/lc337.html