Maximal Square
2015-11-03 21:59
141 查看
Given a 2D binary matrix filled with 0's and 1's, find the largest square containing all 1's and return its area.
For example, given the following matrix:
Return 4.
[思路]
dynamic programing. 以当前点(x,y) = '1' 为右下角的最大正方形的边长f(x,y) = min( f(x-1,y), f(x,y-1), f(x-1,y-1)) + 1.
递推公式已建立, dp就自然而然了.
For example, given the following matrix:
1 0 1 0 0 1 0 1 1 1 1 1 1 1 1 1 0 0 1 0
Return 4.
[思路]
dynamic programing. 以当前点(x,y) = '1' 为右下角的最大正方形的边长f(x,y) = min( f(x-1,y), f(x,y-1), f(x-1,y-1)) + 1.
递推公式已建立, dp就自然而然了.
public class Solution { public int maximalSquare(char[][] matrix) { if(matrix==null || matrix.length==0 || matrix[0].length==0) return 0; int n = matrix.length; int m = matrix[0].length; int[][] d = new int [m]; int max = 0; for(int i=0; i<n; i++) { if(matrix[i][0]=='1') { d[i][0] = 1; max = 1; } } for(int j=0; j<m; j++) { if(matrix[0][j]=='1') { d[0][j] = 1; max = 1; } } for(int i=1; i<n; i++) { for(int j=1; j<m; j++) { if(matrix[i][j]=='0') d[i][j]=0; else { d[i][j] = Math.min( Math.min( d[i-1][j], d[i][j-1]), d[i-1][j-1] ) + 1; max = Math.max(max, d[i][j]); } } } return max*max; } }
相关文章推荐
- 盘古搜索--实例解析
- Unity3D Editor模式下批量修改prefab
- 烦躁KMP
- mysql连接查询
- 信号量和互斥锁有什么区别??
- java与c#的语法区别详细介绍
- 深扒朋友圈疯传两大金融传销骗局
- swift 编写欢迎界面-- ios开发
- 字符串和字符数组
- 安装RabbitMQ遇到的问题
- 帕金森定律(Parkinson's Law)
- CodeForces 501B——Misha and Changing Handles
- POJ 2965The Pilots Brothers' refrigerator
- IP地址分类与子网划分
- HDU 1026 Ignatius and the Princess I(BFS+优先队列+路径记录)
- CloudSuite之Graph Analytics集群安装
- MySQL中的事务
- git学习
- LeetCode OJ:Intersection of Two Linked Lists(两个链表的插入)
- jsPlumb之import and setup(翻译,未完待续......)