Bug Report for search-for-word-ii

[RaghavGupta-01]

Bug Report for https://neetcode.io/problems/search-for-word-ii

Getting 27/29 test cases passed on two different solutions - both fail on test case 28 with a runtime error (confirmed via AddressSanitizer).

1. My own solution:

class TrieNode {
   public:
    TrieNode* child[26];
    string word;
    TrieNode() {
        for (int i = 0; i < 26; i++) {
            child[i] = NULL;
        }
        word = "";
    }
};
class Solution {
   public:
    vector<string> res;
    int rows, cols;

    void insert(TrieNode* root, string& word) {
        TrieNode* curr = root;
        for (char ch : word) {
            int idx = ch - 'a';
            if (curr->child[idx] == NULL) {
                curr->child[idx] = new TrieNode();
            }
            curr = curr->child[idx];
        }
        curr->word = word;
    }

    void dfs(vector<vector<char>>& board, TrieNode* node, int r, int c) {
        if (r < 0 || r >= rows || c < 0 || c >= cols) {
            return;
        }

        if (board[r][c] == '#') {
            return;
        }

        char ch = board[r][c];
        TrieNode* next = node->child[ch - 'a'];

        if (next == NULL) {
            return;
        }
        if (!next->word.empty()) {
            res.push_back(next->word);
            next->word = "";
        }
        board[r][c] = '#';

        dfs(board, next, r - 1, c);
        dfs(board, next, r + 1, c);
        dfs(board, next, r, c - 1);
        dfs(board, next, r, c + 1);
        board[r][c] = ch;
    }
    vector<string> findWords(vector<vector<char>>& board, vector<string>& words) {
        res.clear();
        rows = board.size();
        cols = board[0].size();

        TrieNode* root = new TrieNode();

        for (string& word : words) {
            insert(root, word);
        }

        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                dfs(board, root, i, j);
            }
        }

        return res;
    }
};

2. The official Solution 3 (Backtracking with Trie) from
   https://neetcode.io/problems/search-for-word-ii/solution
   also fails on the same test case with the same kind of error.

Failing input (test case 28):

board=[["b","a","b","a","b","a","b","a","b","a"],["a","b","a","b","a","b","a","b","a","b"],["b","a","b","a","b","a","b","a","b","a"],["a","b","a","b","a","b","a","b","a","b"],["b","a","b","a","b","a","b","a","b","a"],["a","b","a","b","a","b","a","b","a","b"],["b","a","b","a","b","a","b","a","b","a"],["a","b","a","b","a","b","a","b","a","b"],["b","a","b","a","b","a","b","a","b","a"],["a","b","a","b","a","b","a","b","a","b"]]
words=["ababababaa","ababababab","ababababac","ababababad","ababababae","ababababaf","ababababag","ababababah","ababababai","ababababaj","ababababak","ababababal","ababababam","ababababan","ababababao","ababababap","ababababaq","ababababar","ababababas","ababababat","ababababau","ababababav","ababababaw","ababababax","ababababay","ababababaz","ababababba","ababababbb","ababababbc","ababababbd","ababababbe","ababababbf","ababababbg","ababababbh","ababababbi","ababababbj","ababababbk","ababababbl","ababababbm","ababababbn","ababababbo","ababababbp","ababababbq","ababababbr","ababababbs","ababababbt","ababababbu","ababababbv","ababababbw","ababababbx","ababababby","ababababbz","ababababca","ababababcb","ababababcc","ababababcd","ababababce","ababababcf","ababababcg","ababababch","ababababci","ababababcj","ababababck","ababababcl","ababababcm","ababababcn","ababababco","ababababcp","ababababcq","ababababcr","ababababcs","ababababct","ababababcu","ababababcv","ababababcw","ababababcx","ababababcy","ababababcz","ababababda","ababababdb","ababababdc","ababababdd","ababababde","ababababdf","ababababdg","ababababdh","ababababdi","ababababdj","ababababdk","ababababdl","ababababdm","ababababdn","ababababdo","ababababdp","ababababdq","ababababdr","ababababds","ababababdt","ababababdu","ababababdv","ababababdw","ababababdx","ababababdy","ababababdz","ababababea","ababababeb","ababababec","ababababed","ababababee","ababababef","ababababeg","ababababeh","ababababei","ababababej","ababababek","ababababel","ababababem","ababababen","ababababeo","ababababep","abab...
input truncated for display

Error output (ASan):