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题目：
Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:
For example,
Consider the following matrix:
[ [1, 3, 5, 7], [10, 11, 16, 20], [23, 30, 34, 50] ]
Given target = 3, return true.
思路：
二分查找
package array; public class SearchA2DMatrix { public boolean searchMatrix(int[][] matrix, int target) { int m; int n; if (matrix == null || (m = matrix.length) == 0 || (n = matrix[0].length) == 0) return false; int start = 0; int end = m * n - 1; while (start <= end) { int mid = (end - start) / 2 + start; int i = mid / n; int j = mid - i * n; if (matrix[i][j] == target) return true; if (matrix[i][j] < target) start = mid + 1; else end = mid - 1; } return false; } public static void main(String[] args) { // TODO Auto-generated method stub int[][] matrix = { { 1, 3, 5, 7 }, { 10, 11, 16, 20 }, { 23, 30, 34, 50} }; SearchA2DMatrix s = new SearchA2DMatrix(); System.out.println(s.searchMatrix(matrix, 8)); } }
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原文地址：http://www.cnblogs.com/shuaiwhu/p/5093203.html
