LeetCode Word Search II，leetcodeii

LeetCode Word Search II，leetcodeii
LeetCode Word Search II題目

思路

結合Trie和DFS即可。
用C寫真是虐心。
也不知道有沒有記憶體泄露。
如有，望指正。

代碼

struct TrieNode {    char c;    // sons for "abcdefghijklmnopqrstuvwxyz\0"    struct TrieNode * son[27];  };struct TrieNode * trieCreate() {    struct TrieNode * trieNode =         (struct TrieNode*)malloc(sizeof(struct TrieNode));    trieNode->c = '\0';    memset(trieNode->son, 0, sizeof(trieNode->son));    return trieNode;}void insert(struct TrieNode * root, char * word) {    if (*word == '\0') {        root->son[26] = trieCreate();        // notice that '\0' is important. There's "abc\0"         // in Trie doesn't mean there's a word "ab\0".        root->son[26]->c = '\0';        return;    }    if (root->son[*word - 'a'] == NULL) {        root->son[*word - 'a'] = trieCreate();        root->son[*word - 'a']->c = *word;        insert(root->son[*word - 'a'], word + 1);    }    else {        insert(root->son[*word - 'a'], word + 1);    }}bool search(struct TrieNode * root, char * word) {    if (*word == '\0') {        // notice that '\0' is important. There's "abc\0"         // in Trie doesn't mean there's a word "ab\0".        if (root->son[26] != NULL) return true;          else return false;    }    if (root->son[*word - 'a'] == NULL) {        return false;    }    else {        return search(root->son[*word - 'a'], word + 1);    }}void trieFree(struct TrieNode* root) {    if (root != NULL) {        for (int i = 0; i < 26; i++) {            trieFree(root->son[i]);        }        free(root);    }}char * AnAns;  // 一個答案char ** Ans;  // 一組答案char ** Board;  // 輸入的boardbool ** vis;  // 是否訪問過int AnsSize;  // 答案的數量int WordsSize;  // 輸入的單詞數量int WordMaxLength;  // 輸入的單詞的最大長度int LastWordSize = 0;  // 上一次的輸入單詞數量int BoardRowSize, BoardColSize;  // board的屬性int dir[4][2] = { -1, 0, 1, 0, 0, -1, 0, 1 };  // 四個方向struct TrieNode * ExistWords, *Root;  // 前者為是否已經找到，後者為建立的Trievoid dfs(struct TrieNode * nowLevel, int pi, int pj, int p) {    if (AnsSize >= WordsSize) return;  // 如果答案數已經達到最大    if (p > WordMaxLength) return;  // 如果位置超過了最長的單詞長度    if (nowLevel->son[26] != NULL) {  // 如果找到了某個單詞的結尾        AnAns[p] = '\0';  // 更改結尾符        if (!search(ExistWords, AnAns)) {  // 如果這個單詞沒有被找到過            insert(ExistWords, AnAns);  // 那麼把它標記為找到過            strcpy(Ans[AnsSize++], AnAns);  // 然後放入答案中        }    }    for (int k = 0; k < 4; k++) {        int gi = pi + dir[k][0];        int gj = pj + dir[k][1];        // 如果在範圍內、沒有訪問過、在Trie中也有這個單詞字母，那就繼續DFS        if (0 <= gi && gi < BoardRowSize && 0 <= gj && gj < BoardColSize            && !vis[gi][gj] && nowLevel->son[Board[gi][gj] - 'a'] != NULL) {            vis[gi][gj] = true;            AnAns[p] = Board[gi][gj];            dfs(nowLevel->son[Board[gi][gj] - 'a'], gi, gj, p + 1);            vis[gi][gj] = false;        }    }}char ** findWords(char ** board, int boardRowSize,    int boardColSize, char ** words, int wordsSize, int * returnSize) {    Root = trieCreate();  // 建立Trie    ExistWords = trieCreate();  // 建立標記Trie    Board = board;    BoardRowSize = boardRowSize;    BoardColSize = boardColSize;    WordsSize = wordsSize;    WordMaxLength = 0;    AnsSize = 0;    // 將所有單詞插入Trie    for (int i = 0; i < wordsSize; i++) {        int Length = strlen(words[i]);        if (Length > WordMaxLength) WordMaxLength = Length;        insert(Root, words[i]);    }    // 初始化vis    vis = (bool**)malloc(sizeof(bool*) * boardRowSize);    for (int i = 0; i < boardRowSize; i++) {        vis[i] = (bool*)malloc(sizeof(bool) * (boardColSize));        for (int j = 0; j < boardColSize; j++) vis[i][j] = false;    }    // 把上一次使用的Ans數組free掉，並建立一個    for (int i = 0; i < LastWordSize; i++) free(Ans[i]);    free(Ans);    LastWordSize = WordsSize;    Ans = (char**)malloc(sizeof(char*) * wordsSize);    for (int i = 0; i < wordsSize; i++) {        Ans[i] = (char*)malloc(sizeof(char) * (WordMaxLength + 1));    }    AnAns = (char*)malloc(sizeof(char*) * (WordMaxLength + 1));    for (int i = 0; i < boardRowSize && !(AnsSize >= wordsSize); i++) {        for (int j = 0; j < boardColSize; j++) {            if (Root->son[board[i][j] - 'a'] != NULL) {                vis[i][j] = true;                AnAns[0] = board[i][j];                dfs(Root->son[board[i][j] - 'a'], i, j, 1);                vis[i][j] = false;                if (AnsSize >= wordsSize) break;            }        }    }    // free    for (int i = 0; i < boardRowSize; i++) free(vis[i]);    free(vis);    free(AnAns);    trieFree(Root);    trieFree(ExistWords);    *returnSize = AnsSize;    return Ans;}