/**
* Initializes a random M-by-N board, according to the frequency of letters in the English
* language.
*
* @param M the number of rows
* @param N the number of columns
*/
public BoggleBoard(int M, int N) {
this.M = M;
this.N = N;
if (M <= 0) {
throw new IllegalArgumentException("number of rows must be a positive integer");
}
if (N <= 0) {
throw new IllegalArgumentException("number of columns must be a positive integer");
}
board = new char[M][N];
for (int i = 0; i < M; i++) {
for (int j = 0; j < N; j++) {
int r = StdRandom.discrete(FREQUENCIES);
board[i][j] = ALPHABET.charAt(r);
}
}
}
