搜索二维矩阵Ⅰ

[

    [1, 3, 5, 7],

    [10, 11, 16, 20],

    [23, 30, 34, 50]

]

public class Solution {
    /**
     * @param matrix, a list of lists of integers
     * @param target, an integer
     * @return a boolean, indicate whether matrix contains target
     */
    public boolean searchMatrix(int[][] matrix, int target) {
        if (matrix == null || matrix.length == 0)
            return false;
        int high = matrix.length - 1;
        int low = 0;
        int mid = 0;
        while (low <= high) {
            mid = (low + high) / 2;
            if (matrix[mid][0] == target)
                return true;
            else if (matrix[mid][0] > target)
                high = mid - 1;
            else
                low = mid + 1;
        }
        int row = mid;
        if (matrix[mid][0] > target) {
            if (mid > 0)
                row = mid - 1;
            else
                return false;
        }
        low = 1;
        high = matrix[0].length - 1;
        while (low <= high) {
            mid = (low + high) / 2;
            if (matrix[row][mid] == target)
                return true;
            else if (matrix[row][mid] > target)
                high = mid - 1;
            else
                low = mid + 1;
        }
        return false;
    }
}