1. 计ç®å¤æåº¦è§è§çè´ªåèé®é¢å½¢å¼åå®ä¹
卿¶å卿éç¢ç©éæï¼Dynamic Reconfiguration with Self-Avoiding Walksï¼ä¸å¾ä¸åå¯é¡¿è·¯å¾ï¼Hamiltonian Path on Grid Graphsï¼çé«ç»´ç¶æè½¬ç§»å¤å®é®é¢ã
ï¼
2. å¤æåº¦çå级çå®ï¼ä» NP-Hard å° PSPACE-Completep>
çº¦æ¥æº / çè®ºä¾æ®
åºå®èèº«ç®æ å¯è¾¾æ§ (Reachability)
ä¸è¬å¾ $G$ æå«å¤è¾¹å½¢éç¢ç©ç½æ ¼å¾ æ 广ä¹éææ¼å¾ (Sokoban) è§çº¦ãè身æå 黿¡ééï¼éææ°
带éç¢ç©ç½æ ¼å¾ $G \subseteq \mathbb{Z}^2$
Path in Grid Graphs, Itai et al., 1982ï¼ã
æ éç¢mn \equiv 0 \pmod 2$)
$P$ (å¤é¡¹å¼æ¶é´å¯è§£)
å¯ç¡®å®æ§æé åå¯é¡¿åè·¯ï¼å¦ Boustrophedon è
NP-Hard / PSPACE-Hard
å³ä¾¿åºå±å¾åå¨ç®ååå¯é¡¿ç¯ï¼ä½å¯»æ¾ä½¿ $\sum \text{dist}(f_i, f_{i+1})$ æå°ä¸å¨ä¸é´å¨æç¶æä¸å½¢æè¿é忝å²éï¼Cut-vertex Deadlockï¼ç转移åºåææä¸¥æ ¼çæä¼åé¾é¢ã
3. 为ä»ä¹â贪婪æçè·¯ (BFS/A*)âä¼å¯¼è´æ»éå´©æºï¼
å¨å·¥ç¨æ°å¦åå å¨äºç½æ ¼å¾çäºåæ§ï¼Bipartitenessï¼ä¸å²ç¹é离ï¼Cut-vertex Separationï¼ï¼
令å©ä½å¯ç¨æ èé¡¶ç¹é为 $V_{\text{free}}(t) = V \setminus \{v_1^t, v_2^t, \dots, v_k^t\}$ã
è¥è´ªå©ªæ¥å¯¼è´ $G[V_{\text{free}}(t)]$ çè¿éåæ¯æ°æ»¡è¶³ï¼
$$c(G[V_{\text{free}}(t)]) > 1 \quad \text{ä¸} \quad \exists C \in \pi_0(G), |C|åäºç¬æ¶æ é $\text{dist}(v_1, f)$ï¼å´æ è§äºè身è身é¿åº¦å¢é¿ï¼è头å¯ç§»å¨è·¯å¾å°ä»¥åææ°é度è缩ã
4. åå¯é¡¿ç¯æé ä¸æçæ¥æ°ä¹é´çå¯¹å¶æè¡¡
卿 éç¢ç $2k \times 2m$ ç©å½¢ç½æ ¼å¾ä¸ï¼ç±äºäºåå¾é»ç½æè²å¹³è¡¡ï¼æ»è½æ¾å¼æé è³å°ä¸æ¡åå¯é¡¿åè·¯èä¸¥æ ¼æ²¿é¢å®çåå¯é¡¿ç¯æ¹åååç¯æ¸¸ï¼è头永è¿å¨è¿½éå䏿¶å»çè身ã
æ¥æ°ä»£ä»·ï¼æå¤§åä½ï¼ï¼ 沿çåºå®åå¯é¡¿ç¯æ¸¸èµ°ï¼æ¯æ¬¡æè·é£ç©æéçæææ¥æ°ä¸ºæ£çé¡¶ç¹æ°çä¸å $\approx \frac{mn}{2}$ãé} \frac{mn}{2} = \mathcal{O}((mn)^2)$$
å¿«æ·åªæï¼Hamiltonian Shortcutsï¼ï¼ å¨ç¡®ä¿è头ä¸èå°¾å¨ç¯ä¸çåºå·ç´¢å¼è·ç¦» $\text{index}(è¡¡ã
5. 常è§é®é¢è§£ç (FAQ)
为ä»ä¹ç½æ ¼å¾Hamilton Paths in Grid Graphsãä¸è¯æï¼å³ä½¿éå¶å¨æ¯ä¸ªé¡¶ç¹åº¦æ°è³å¤ä¸º 4 çæ åå¹³é¢ç½æ ¼è¯±çº¦å°æ åå¹³é¢å¾ï¼åéè¿ç²¾å·§çæ£æ¹å½¢ç½æ ¼çº¿æ®µä¸è¿æ¥ç»ä»¶æ¿æ¢æé åæä»¶ï¼Tentacles & Clauses Gadgetsï¼å®æçãå æ¤å¨å¸¦éç¢ç©çè´ªåèæ£çä¸ï¼å¤æå¯é¡¿ç¯ï¼æ¶é´å¤æåº¦ä¸º $O(N)$ï¼ãèâæçæ¥æ°âè¦æ±å¨ææå¯è½çèªé¿è¡èµ°åå²åæ¯ä¸æå°åç§¯åæ¥æ°ï¼è¿ææäºé«ç»´å¨æè§åé®é¢ãæ¯ä¸ä¸ªå³çé½ä¼ä¸å¯éå°æ¹åæªæ¥å ç¾æ¥çåæ³å ä½èµ°å»ï¼æç´¢æ 深度为 $\Theta(|V|^2)$ï¼åæ¯å åå¨ 2 å° 3 ä¹é´ï¼è¿å¼åäºä¸¥èçç¶æç©ºé´çç¸ã
æ°ï¼
深度强åå¦ä¹ ï¼å¦ DQN æ PPOï¼å¨å°è§æ¨¡ç½æ ¼ä¸å¯ä»¥éè¿å¥å±å¡å½¢å¦å°é常åºè²çâè¿ééæ©âçç¥ï¼ä½ä»å½èèº«å æ® 80% 以ä¸ç½æ ¼æ¶ï¼ä»·å¼å½æ°è¿ä¼¼ï¼Value Function Approximationï¼ä¼åºç°ä¸¥éçèªâã
| çº¦æ¥æº / çè®ºä¾æ® | ||||
|---|---|---|---|---|
| åºå®èèº«ç®æ å¯è¾¾æ§ (Reachability) | ä¸è¬å¾ $G$ æå«å¤è¾¹å½¢éç¢ç©ç½æ ¼å¾ æ 广ä¹éææ¼å¾ (Sokoban) è§çº¦ãè身æå 黿¡ééï¼éææ° | 带éç¢ç©ç½æ ¼å¾ $G \subseteq \mathbb{Z}^2$ | Path in Grid Graphs, Itai et al., 1982ï¼ã | |
| æ éç¢mn \equiv 0 \pmod 2$) | $P$ (å¤é¡¹å¼æ¶é´å¯è§£) | å¯ç¡®å®æ§æé åå¯é¡¿åè·¯ï¼å¦ Boustrophedon è | NP-Hard / PSPACE-Hard | å³ä¾¿åºå±å¾åå¨ç®ååå¯é¡¿ç¯ï¼ä½å¯»æ¾ä½¿ $\sum \text{dist}(f_i, f_{i+1})$ æå°ä¸å¨ä¸é´å¨æç¶æä¸å½¢æè¿é忝å²éï¼Cut-vertex Deadlockï¼ç转移åºåææä¸¥æ ¼çæä¼åé¾é¢ã |
3. 为ä»ä¹â贪婪æçè·¯ (BFS/A*)âä¼å¯¼è´æ»éå´©æºï¼
å¨å·¥ç¨æ°å¦åå å¨äºç½æ ¼å¾çäºåæ§ï¼Bipartitenessï¼ä¸å²ç¹é离ï¼Cut-vertex Separationï¼ï¼
4. åå¯é¡¿ç¯æé ä¸æçæ¥æ°ä¹é´çå¯¹å¶æè¡¡
卿 éç¢ç $2k \times 2m$ ç©å½¢ç½æ ¼å¾ä¸ï¼ç±äºäºåå¾é»ç½æè²å¹³è¡¡ï¼æ»è½æ¾å¼æé è³å°ä¸æ¡åå¯é¡¿åè·¯èä¸¥æ ¼æ²¿é¢å®çåå¯é¡¿ç¯æ¹åååç¯æ¸¸ï¼è头永è¿å¨è¿½éå䏿¶å»çè身ã