leetCode_字典树

好吧，又写了一遍字典树，已经写了n遍了。不过希望下次把线段树学会~

上代码：

class TrieNode {
public:
    int tag;
    TrieNode *next[26];
    // Initialize your data structure here.
    TrieNode() {
        int i;
        for(i=0;i<26;i++) next[i]=NULL;
        tag=0;
    }
};

class Trie {
public:

    Trie() {
        root = new TrieNode();
    }

    // Inserts a word into the trie.
    void insert(string word) {
        TrieNode *tempRoot=root;
        int i;
        for(i=0;inext[word[i]-'a']==NULL)
            {
                TrieNode * newNode=new TrieNode();
                tempRoot->next[word[i]-'a']=newNode;
            }
            tempRoot=tempRoot->next[word[i]-'a'];
        }
        tempRoot->tag=1;
    }

    // Returns if the word is in the trie.
    bool search(string word) {
        TrieNode *tempRoot=root;
        int i;
        for(i=0;inext[word[i]-'a']!=NULL) tempRoot=tempRoot->next[word[i]-'a'];
            else return false;
        }
        return tempRoot->tag==1;
    }

    // Returns if there is any word in the trie
    // that starts with the given prefix.
    bool startsWith(string word) {
        TrieNode *tempRoot=root;
        int i;
        for(i=0;inext[word[i]-'a']!=NULL) tempRoot=tempRoot->next[word[i]-'a'];
            else return false;
        }
        return true;
    }

private:
    TrieNode* root;
};