LeetCode85 Maximal Rectangle Java

public static int Maximalrectangle (char[][] matrix) {  int rownum=matrix.length; if (rownum==0) return 0; int Columnnum =matrix[0].length;   Int[][] Height=new int[rownum][columnnum+1]; int maxarea=0;  for (int i=0;i<rownum;i++) {for (int j=0;j<columnnum;j++) {int k=i, height[i][j]=0; while (k>=0&&j< Columnnum) {if (matrix[k][j]== ' 1 ') height[i][j]++; else break;  k--; }  } height[i][columnnum]=-1; }  stack<integer> stack=new stack<> (); for (int. i=0;i<rownum;i++) {for (int j=0;j<=columnnum;j++) {int a=height[i][j]; int b=stack.isempty ()? -1:stack.peek (); if (Stack.isempty () | | Height[i][j]>=height[i][stack.peek ()]) Stack.push (j); else  {int temppop=stack.pop (); Maxarea=math.max (Maxarea, height[i][temppop]* (Stack.isempty ()?
J:j-1-stack.peek ())); j--; }} stack.clear (); }  return maxarea;            }

Topic:

Given a 2D binary matrix filled with 0 's and 1 ' s, find the largest rectangle containing all ones and return to its area.

That is, for a 2-dimensional matrix with only 0 and 1, the maximum square area of 1 can be composed.

Solving:

This question can be regarded as the extension of the previous question (LeetCode84), the previous question entered an array, the value of each element of the array as the height of the rectangle, in this problem first to do a processing of the matrix. The height of the element of the matrix is computed, and after processing it is given a height matrix of each primitive matrix element, and the matrix as input is similar to the previous question.

Code:

LeetCode85 Maximal Rectangle Java