Open larscheng opened 5 months ago
class Solution { public boolean exist(char[][] board, String word) { int m = board.length; int n = board[0].length; boolean[][] used = new boolean[m][n]; for (int i = 0; i < m; i++) { for (int j = 0; j < n; j++) { if (check(board, used, i, j, word, 0)) { return true; } } } return false; }
private boolean check(char[][] board, boolean[][] used, int i, int j, String word, int k) {
if (board[i][j] != word.charAt(k)) {
return false;
} else if (k == word.length() - 1) {
return true;
}
boolean result = false;
used[i][j] = true;
int[][] directions = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
for (int[] direction : directions) {
//递归逐个找相邻元素,一直找到不想等的,或者找到最后一个字符结束
int newI = direction[0] + i;
int newJ = direction[1] + j;
if (newI >= 0 && newI < board.length && newJ >= 0 && newJ < board[0].length) {
if (!used[newI][newJ] && check(board, used, newI, newJ, word, k + 1)) {
result = true;
break;
}
}
}
used[i][j] = false;
return result;
}
}
79. 单词搜索