Grokking 202

class Solution {
  public int maximalSquare(char[][] matrix) {
    int rows = matrix.length;
    int cols = matrix[0].length;

    int[][] dp = new int[rows + 1][cols + 1];

    int maxsqlen = 0;

    for (int row = 1; row <= rows; row++) {
      for (int col = 1; col <= cols; col++) {

        if (matrix[row - 1][col - 1] == '1') {
          dp[row][col] = 1 + Math.min(
            dp[row - 1][col - 1],
            Math.min(dp[row - 1][col], dp[row][col - 1])
          );

          maxsqlen = Math.max(maxsqlen, dp[row][col]);
        }

      }
    }

    return maxsqlen * maxsqlen;
  }
}