Coursera algorithm two week 4 boggle

This time the work mainly uses the word search tree and the depth first search.

1. In the depth-first search, mark the marked array as true before the recursive invocation of the current layer. When a recursive call is returned to the current layer, the marked array should be marked as false. This allows you to not access the nodes on the current node path after the current node has been accessed, but to access the node from other paths.

2. When no word in the dictionary is prefixed with the string that reaches the current node, the depth-first search is stopped.

3. Rewrite the word lookup tree and R to 26 to avoid consuming too much space. In addition, the Keyswithprefix function is changed to the Haskeyswithprefix function because there is no need to find all the words prefixed with a string, but only to determine if there is a word prefixed with a string.

1 ImportJava.util.HashSet;2 ImportJava.util.Set;3 4  Public classBogglesolver5 {6     PrivateTrieSET2 dictionary =NewTrieSET2 ();7     8      Publicbogglesolver (string[] dictionary)9     {Ten          for(String s:dictionary) One              This. Dictionary.put (s); A     } -     Private intm, N; -      PublicIterable<string>getallvalidwords (boggleboard board) the     { -Set<string> set =NewHashset<string>(); -m =board.rows (); -n =board.cols (); +          for(inti = 0; I < m; i++) -         { +              for(intj = 0; J < N; J + +) A             { atmarked =New Boolean[m][n]; -DFS (set, board, I, J, "")); -             } -         } -         returnset; -     } in     Private Boolean[] marked; -     Private BooleanIsmarked (intIintj) to     { +         if(I < 0 | | I >= m | | J < 0 | | J >=N) -             return true; the         returnMarked[i][j]; *     } $     Private voidDFS (set<string> Set, Boggleboard board,intIintJ, String s)Panax Notoginseng     { -         Charc =Board.getletter (i, j); the         if(c = = ' Q ') s + = "QU"; +         Elses + =C; A         if(!dictionary.haskeyswithprefix (s))return; theMARKED[I][J] =true; +         if(S.length () > 2 &&Dictionary.contains (s)) - Set.add (s); $          for(intK =-1; K < 2; k++) $         { -              for(intL =-1; L < 2; l++) -             { the                 if(!ismarked (i + K, j +l)) -DFS (set, board, i + K, j +L, s);Wuyi             } the         } -MARKED[I][J] =false; Wu     } -      About      Public intscoreof (String word) $     { -         if(!dictionary.contains (word)) -             return0; -         intLength =word.length (); A         if(Length < 3)return0; +         Else if(Length < 5)return1; the         Else if(length = = 5)return2; -         Else if(length = = 6)return3; $         Else if(length = = 7)return5; the         Else return11; the     } the}

1 ImportEdu.princeton.cs.algs4.Queue;2 3  Public classTrieSET24 {5     Private Static intR = 26;6     PrivateNode Root;7     8     Private Static classNode9     {Ten         Private BooleanHasword; One         PrivateNode[] Next =NewNode[r]; A     } -      -      Public voidput (String key) the     { -Root = put (root, key, 0); -     } -      +     Private intCharAt (String S,intd) -     { +         returnS.charat (d)-' A '; A     } at      -     PrivateNode put (node x, String key,intd) -     { -         if(x = =NULL) x =NewNode (); -         if(d = =key.length ()) -         { inX.hasword =true; -             returnx; to         } +         intc =charAt (key, D); -X.next[c] = put (x.next[c], key, d+1); the         returnx; *     } $     Panax Notoginseng      Public Booleancontains (String key) -     { theNode x = Get (root, key, 0); +         if(x = =NULL)return false; A         returnX.hasword; the     } +      -     PrivateNode get (node X, String key,intd) $     { $         if(x = =NULL)return NULL; -         if(d = = Key.length ())returnx; -         intc =charAt (key, D); the         returnGet (X.next[c], key, d+1); -     }Wuyi      the      Public BooleanHaskeyswithprefix (String Pre) -     { Wu         returnGet (root, Pre, 0)! =NULL; -     } About}

Coursera algorithm two week 4 boggle