CYK algorithm implementation java -

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i'm trying implement cyk algorithm based on wikipedia pseudocode. when test string "a b" grammar input:

s->a b

a->a

b->b

gives me false, , think should true. have arraylist called allgrammar contains rules. example above contain:

[0]: s->a b
[1]: a->a
[2]: b->b

for example s->hello , input string hello gives me true should. more complex tests (more productions) gives me false :s

public static boolean cyk(string entrada) {     int n = entrada.length();     int r = allgrammar.size();     //vector<string> startingsymbols = getsymbols(allgrammar);     string[] ent = entrada.split("\\s");     n = ent.length;     system.out.println("length of entry" + n);     //let p[n,n,r] array of booleans. initialize elements of p false.     boolean p[][][] = initialize3dvector(n, r);     //n-> number of words of string entrada,      //r-> number of nonterminal symbols      //this grammar contains subset rs set of start symbols     (int = 1; < n; i++) {         for(int j = 0; j < r; j++) {             string[] rule = (string[]) allgrammar.get(j);             if (rule.length == 2) {                 if (rule[1].equals(ent[i])) {                     system.out.println("entrou");                     system.out.println(rule[1]);                     p[i][1][j + 1] = true;                 }             }         }     }     for(int = 2; < n; i++) {         system.out.println("first:" + i);          for(int j = 1; j < n - + 1; j++) {             system.out.println("second:" + j);              for(int k = 1; k < - 1; k++) {                 system.out.println("third:" + k);                 for(int g = 0; g < r; g++) {                     string[] rule = (string[]) allgrammar.get(g);                     if (rule.length > 2) {                         int = returnpos(rule[0]);                         int b = returnpos(rule[1]);                         int c = returnpos(rule[2]);                         system.out.println("a" + a);                         system.out.println("b" + b);                         system.out.println("c" + c);                         if (a!=-1 && b!=-1 && c!=-1) {                             if (p[j][k][b] && p[j + k][i - k][c]) {                                 system.out.println("entrou2");                                 p[j][i][a] = true;                             }                         }                     }                 }             }         }     }      for(int x = 0; x < r; x++) {         if(p[1][n][x]) return true;     }      return false; }

as compared cyk algorithm:

  • you have indexing starting @ 1, arrays appear start @ 0
  • the function returnpos() not defined, , it's not obvious does.

it seem problems basic in the use of indexes. if new language, might want refresher.


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