leetcode 74. 搜索二维矩阵

class Solution {
    public boolean searchMatrix(int[][] matrix, int target) {
        int m = matrix.length;
        int n = matrix[0].length;
        int l = 0;
        int r = n * m - 1; // 记得减一
        while (l <= r) {
            int mid = (l + r) / 2;
            if(matrix[mid / n][mid % n] > target) {
                r = mid - 1;
            } else if (matrix[mid / n][mid % n] < target){
                l = mid + 1;
            } else {
                return true;
            }
        }
        return false;
    }
}