L2：06 - Search a 2D Matrix_ninechapter search a 2d matrix-优快云博客

本文介绍了一种高效的搜索算法，用于在一特殊性质的二维矩阵中查找特定值。该矩阵的每一行从左到右递增排序，并且每行的第一个元素大于前一行的最后一个元素。文章提供了一个具体的例子和实现代码。

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Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted from left to right. The first integer of each row is greater than the last integer of the previous row. For example, Consider the following matrix: [ [1, 3, 5, 7], [10, 11, 16, 20], [23, 30, 34, 50] ] Given target = 3, return true.

http://answer.ninechapter.com/solutions/search-a-2d-matrix/

/**
 * Copyright: NineChapter
 * - Algorithm Course, Mock Interview, Interview Questions
 * - More details on: http://www.ninechapter.com/
 */

public class Solution {
    public boolean searchMatrix(int[][] matrix, int target) {
        int rows = matrix.length;
        int cols = matrix[0].length;
        int start = 0;
        int end = rows * cols - 1;
        while (start <= end) {
            int mid = (start + end) / 2;
            // Tricks to treat it as a 1-D array
            int digit = matrix[mid / cols][mid % cols];
            if (target == digit) {
                return true;
            } else if (target > digit) {
                start = mid + 1;
            } else {
                end = mid - 1;
            }
        }
        return false;
    }
}