Search a Sorted 2D Matrix

Each row of `matrix` is sorted ascending, and the first value of each row is greater than the last value of the previous row. Return whether `target` is in the matrix, in O(log(rows · cols)) time. **Example 1:** ``` Input: matrix = [[1, 3, 5, 7], [10, 11, 16, 20], [23, 30, 34, 60]], target = 3 Output: true ``` **Example 2:** ``` Input: matrix = [[1, 3, 5, 7], [10, 11, 16, 20], [23, 30, 34, 60]], target = 13 Output: false ``` **Example 3:** ``` Input: matrix = [[1]], target = 1 Output: true ```