一、枚举所有宽度为举着宽度的子矩阵，从中找出是否具有相应长度的正方形，复杂度为O（n^3）；二、[1]中使用动态规划，decrease the complexity to O(n^2)dp[i][j] mean the maximum square which has right-down corner (i,j)the transform function is listed as below:dp[i][j] = min(dp[i-1][j],dp[i][j-1],dp[i-1][j])+1;
[1] http://www.cnblogs.com/easonliu/p/4548769.html
[Leetcode] Maximal Square
原文：http://www.cnblogs.com/deepblueme/p/4694064.html
