枚舉階段中的所有n-gram子詞

Question

任何現有的可以處理此問題的函數？ 輸入：A B C 輸出：{A}，{B}，{C}，{A B}，{B C}，{A B C}

注意，{A C}或{C A}是無效的輸出。

Answer 1

在僞碼：

for (i=0 .. n-1) { 
    for (j=i .. n-1) { 
     ngrams.add(phase[i:j]) 
    } 
} 

phase[i:j]是切片起始於i和在j和n結束時的長度（在這種情況下3）

A B C 
0 1 2 

0:0 A 
0:1 AB 
0:2 ABC 
1:1 B 
1:2 BC 
2:2 C 

Answer 2

我計算出來：O型（n^3）算法

public static void GenerateAllGrams(string query) { 
     string[] q = query.Split(' '); 
     int maxgram = q.Length; 
     for (int gram = 1; gram <= maxgram; gram++) { 
      for (int i = 0; i < q.Length - gram + 1; i++) { 
       string current = ""; 
       for (int j = i; j < i + gram; j++) { 
        current += q[j] + " "; 
       } 
       Console.WriteLine(current.Trim()); 
      } 
     } 
    } 

Answer 3

在方案中：

(define (prefix x list) 
    (if (null? list) 
     nil 
     (cons (cons x (car list)) 
       (prefix x (cdr list))))) 

(define (subwords phrase) 
    (if (null? phrase) 
     nil 
     (cons (list (car phrase)) 
       (cons (prefix (car phrase) (subwords (cdr phrase))) 
        (subwords (cdr phrase))))))