作者:jostree 转载请注明出处 http://www.cnblogs.com/jostree/p/4052721.html 题目链接:leetcode Maximal Rectangle 单调栈 该题目是  leetcode Largest Rectangle in Histogram 的二维版本,首先进行预处理,把一个n×m的矩阵化为n个直方图,然后在每个直方图中计算使用单调栈的方法计算面积最大的矩形,然后求得最大的矩形面积即可. Ps:这题直接在网页里面敲完居然1A,不错. 代码如下:…

Maximal RectangleGiven a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and return its area. Show TagsHave you met this question in a real interview? Yes  NoDiscussSOLUTION 1: public class Solution { public i…

Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and return its area. 此题是之前那道的Largest Rectangle in Histogram 直方图中最大的矩形 的扩展,这道题的二维矩阵每一层向上都可以看做一个直方图,输入矩阵有多少行,就可以形成多少个直方图,对每个直方图都调用Largest Rectangle in Hist…

原题地址:https://oj.leetcode.com/problems/maximal-rectangle/ 题意:Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and return its area. 解题思路:找出矩阵中最大的矩形,矩形中只包含1.这道题需要利用上一道题(Largest Rectangle in Histogram)的结论.比…

Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and return its area. 在做Largest Rectangle in Histogram的时候有人说可以用在这题,看了一下还真是,以每行为x轴,每列往上累计的连续的1当成高度,就可以完全使用一样的方法了. int largestArea(vector<int>height){ stac…

Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and return its area. 参考“Largest Rectangle in Histogram”这个题的解法,思想差不多一样,只是用h向量表示Rectangle中此元素中第一行到本行的高度,非常妙的算法: class Solution { public: int maximalRectang…

Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and return its area. [解题思路] 1.brute force 枚举所有sub-matrix(O(N^2), N = m*n) ,检查每个子矩阵是不是都是1,如果是更新最大面积,检查子矩阵是否都是1需要 花费O(N). 故总的时间为O(N^3) N = m*n 可以过小数据,大数据直接…

之前切了道求解最大正方形的题,题解猛戳 这里.这道题 Maximal Rectangle 题意与之类似,但是解法完全不一样. 先来看这道题 Largest Rectangle in Histogram,如果暴力求解,可以枚举每个点为最小值,向两边扩展,复杂度 O(n^2).我们可以维护一个栈,从而将复杂度降低到 O(n),这个栈的思维非常巧妙,参考了 discuss,我是完全想不出来(或者说忘记了).具体代码可以猛戳 这里. 2016-08-07 补:stack 数组维护的是一个单调递增的数组,…

leetcode面试准备: Maximal Rectangle 1 题目 Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and return its area. 接口: int maximalRectangle(char[][] matrix) 2 思路 这是一道非常综合的题目,要求在0-1矩阵中找出面积最大的全1矩阵.刚看到这道题会比较无从下手,b…

Largest Rectangle in Histogram Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram. Above is a histogram where width of each bar is 1, given heigh…

Maximal Rectangle Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and return its area.     使用dpHeight[]数组来记录到第i行为止,第j个位置垂直连续包含多少个1(包括matrxi[i][j]).如: 1 0 1 1 0 1 1 0 1 0 0 1 1 1 1 有如下结果: 第1行: dpHeight[…

1. Maximal Square 题目链接 题目要求: 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. 在GeeksforGeeks有一个解决该问题的方法: 1) Construct a sum matrix S[R…

Maximal Rectangle Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and return its area. 如果用DP来做,判断(begin1,end1)~(begin2,end2)范围是否全1,会超时. 对于矩阵matrix,逐行构建height数组,调用Largest Rectangle in Histogram即可. 对matr…

84题和85五题 基本是一样的,先说84题 84--柱状图中最大的矩形( Largest Rectangle in Histogram) 思路很简单,通过循环,分别判断第 i 个柱子能够延展的长度len,最后把len*heights[i] 就是延展开的面积,最后做比对,得出最大. public int largestRectangleArea(int[] heights) { int ans=0; for(int i=0;i<heights.length;i++) { int len=1,lef…

Given a rows x cols binary matrix filled with 0's and 1's, find the largest rectangle containing only 1's and return its area. Example 1: Input: matrix = [["1","0","1","0","0"],["1","0"…

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: 1 0 1 0 0 1 0 1 1 1 1 1 0 0 1 0 Return 4. Credits:Special thanks to @Freezen for adding this pr…

Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram. Above is a histogram where width of each bar is 1, given height = [2,1,5,6,2,3]. The largest…

Given a 2D boolean matrix filled with False and True, find the largest rectangle containing all True and return its area. ExampleGiven a matrix: [ [1, 1, 0, 0, 1], [0, 1, 0, 0, 1], [0, 0, 1, 1, 1], [0, 0, 1, 1, 1], [0, 0, 0, 0, 1]]return 6. LeetCode上…

原题链接在这里:https://leetcode.com/problems/maximal-square/ 这是一道DP题,存储历史信息是到当前点能有的最大square, 用二维数组dp存储. 更新方式是若当前点为0,则不更新,若当前点为1,则取上dp[i-1][j], 左dp[i][j-1], 左上dp[i-1][j-1]的中的最小值,开根号加一,最后平方为dp[i][j]. 初始第一行和第一列,为'1'的时候填成1. Note: 1. 给的matrix数组是char, 所以比较时是根char…

这两天在做leetcode的题目,最大矩形的题目以前遇到很多次了,一直都是用最笨的方法,扫描每个柱子,变换宽度,计算矩形面积,一直都以为就这样O(n2)的方法了,没有想到居然还有研究出了O(n)的算法,真是对GeeksForGeeks大神膜拜啊. 首先是Largest Rectangle in Histogram这个题目 class Solution { public: int largestRectangleArea(vector<int> &height) { int len=he…

85. Maximal Rectangle Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing only 1's and return its area. For example, given the following matrix: 1 0 1 0 0 1 0 1 1 1 0 0 1 0 Return 6.…

Largest Rectangle in Histogram Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram. Above is a histogram where width of each bar is 1, given heigh…

作者:jostree 转载请注明出处 http://www.cnblogs.com/jostree/p/4052343.html 题目链接 leetcode Largest Rectangle in Histogram 单调栈 对于每一个长条都向前找包含这个长条的最大面积使可行的,但是时间复杂度是O(n^2)大数据会超时.经过观察发现并不需要对每一个长条都向前查找,对于height[i],如果height[i+1]>height[i],那么就没有必要向前查找,原因是可以从height[i]查找到…

2018-09-15 10:23:44 一.Largest Rectangle in Histogram 在求解最大的矩形面积之前,我们先讨论一条最大直方图面积的问题. 问题描述: 问题求解: 解法一.朴素解法,O(n ^ 2). 解决的思路就是遍历一遍,如果当前的数比后一个数要小,那么当前的额数字肯定不可能是最大面积的右边界,遍历下一个数: 如果当前数比后一个大,那么假设当前的为右边界,向左进行遍历,计算面积最大值. public int largestRectangleArea(int[]…

Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and return its area. 思路: 例如 01101 11010 01110 11110 11111 00000 按列从上到下计算maximal rectangle: 01101 12010 03110 14210 25321 00000 然后对每一行求直方图的最大面积,于是这个问题可以转化…

LintCode 510: Maximal Rectangle 题目描述 给你一个二维矩阵,权值为False和True,找到一个最大的矩形,使得里面的值全部为True,输出它的面积 Wed Nov 24 2016 思路 本题的思路比较多,可以用动态规划,也可以把本题看做是最长连续正数列的二维版本,还可以把本题看做多个求柱形图中得最大矩形问题. 如果用动态规划,记\(f(i, j, l)\)为以\((i, j)\)为左上角顶点,以\(l\)为列宽的矩形面积.指定\(i\),\(j\),通过变换\(…

一.题目说明 题目,85. Maximal Rectangle,计算只包含1的最大矩阵的面积.难度是Hard! 二.我的解答 看到这个题目,我首先想到的是dp,用dp[i][j]表示第i行第j列元素向右下角计算的最大面积.后来发现从dp[i+1][j].dp[i][j+1]和dp[i+1][j+1]计算dp[i][j]几乎没有任何规律可循. 然后,我就想用down_dp[i][j]和right_dp[i][j]两个dp,但遗憾的是还是没成功. 后面看了大神的写法,其实down_dp[i][j]然…

Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing only 1's and return its area. Example: Input: [ ["1","0","1","0","0"], ["1","0","1",&qu…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 题目地址: https://leetcode.com/problems/maximal-rectangle/description/ 题目描述: Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing only 1's and return its area. Exa…

链接: https://leetcode.com/problems/maximal-rectangle/ [描述] Given a 2D binary matrix filled with '0's and '1's, find the largest rectangle containing all ones and return its area. [中文描述] 给一个二维数组, 算出里面最大的全1矩形面积,比如: [ ['1','1','1','0'], ['1','1','1','1']…