使用二分查找来解决该问题。这道题使用二分查找算法的核心点在于一维索引 mid 对应的二维矩阵位置换算公式 matrix[mid / n][mid % n]

class Solution {
    public boolean searchMatrix(int[][] matrix, int target) {
        int rows = matrix.length;
        int cols = matrix[0].length;
        int left = 0;
        int right = rows * cols - 1;

        while(left <= right) {
            int mid = left + (right - left) / 2;
            int midValue = matrix[mid / cols][mid % cols];
            if(midValue == target) {
                return true;
            } else if(midValue > target) {
                right = mid - 1;
            } else {
                left = mid + 1;
            }
        }
        return false;
    }
}