1032 done

Author: aQuaYi

Algorithms/1032.stream-of-characters/stream-of-characters.go

@@ -2,62 +2,58 @@ package problem1032
 
 // StreamChecker check letters
 type StreamChecker struct {
-	tree   *trie
-	stream []int8
 	max    int
+	trie   *trie
+	stream []int8
 }
 
 // Constructor returns StreamChecker
 func Constructor(words []string) StreamChecker {
-	maxLen := 0
-	tree := &trie{}
-	for _, word := range words {
-		maxLen = max(maxLen, len(word))
-		tree.insert(word)
+	m := 0
+	t := &trie{}
+	for _, w := range words {
+		m = max(m, len(w))
+		t.insert(w)
 	}
 	return StreamChecker{
-		tree:   tree,
-		stream: make([]int8, 0, 40001),
-		max:    maxLen,
+		max:    m,
+		trie:   t,
+		stream: make([]int8, 0, 1024),
 	}
 }
 
 // Query returns true if letter in words
 func (sc *StreamChecker) Query(letter byte) bool {
 	sc.stream = append(sc.stream, int8(letter-'a'))
-	n := len(sc.stream)
-	cur := sc.tree
+	n, t := len(sc.stream), sc.trie
 	for i := 1; i <= sc.max && i <= n; i++ {
 		index := sc.stream[n-i]
-		if cur.next[index] == nil {
+		if t.next[index] == nil {
 			return false
 		}
-		cur = cur.next[index]
-		if cur.isWord {
+		t = t.next[index]
+		if t.isWord {
 			return true
 		}
 	}
 	return false
 }
 
-// TODO:   var isWord = &trie{}
-
 type trie struct {
 	next   [26]*trie
 	isWord bool
 }
 
 func (t *trie) insert(word string) {
 	n := len(word)
-	cur := t
 	for i := n - 1; i >= 0; i-- {
 		index := int(word[i] - 'a')
-		if cur.next[index] == nil {
-			cur.next[index] = &trie{}
+		if t.next[index] == nil {
+			t.next[index] = &trie{}
 		}
-		cur = cur.next[index]
+		t = t.next[index]
 		if i == 0 {
-			cur.isWord = true
+			t.isWord = true
 		}
 	}
 }

Algorithms/1032.stream-of-characters/stream-of-characters_test.go

@@ -94,3 +94,14 @@ func Test_Case_6(t *testing.T) {
 		ast.Equal(expects[i], streamChecker.Query(q), "%d:%s", i, string(querys[:i+1]))
 	}
 }
+
+func Test_Case_7(t *testing.T) {
+	ast := assert.New(t)
+	//
+	words := []string{"cd"}
+	streamChecker := Constructor(words)
+	//
+	ast.False(streamChecker.Query('c')) // return false
+	ast.False(streamChecker.Query('a')) // return false
+	ast.False(streamChecker.Query('d')) // return false
+}