数学、计算几何、位运算常见问题详解

    public int searchMatrix(int[][] matrix, int target) {
        // write your code here
        int n = matrix.length;
        if (n == 0) {
            return 0;
        }
        int m = matrix[0].length;
        if (m == 0) {
            return 0;
        }
        int i = n - 1;
        int j = 0;
        int res = 0;
        while (i >= 0 && j < m) {
            if (matrix[i][j] == target) {
                res++;
                i--;
                j++;
            } else if (matrix[i][j] > target) {
                i--;
            } else {
                j++;
            }
        }
        return res;
    }