《leetCode》： Maximal Rectangle

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.

思路

这个题目确实比较难，做不出来，在讨论组看到的别人的解法，借助了上一个题的思路。

public int maximalRectangle(char[][] matrix) {        if(matrix==null||matrix.length<1||matrix[0].length<1){            return 0;        }        int height[]=new int[matrix[0].length];        for(int i=0;i<matrix[0].length;i++){            if(matrix[0][i]=='1'){                height[i]=1;            }        }        int res=largestInLine(height);        for(int row=1;row<matrix.length;row++){            for(int col=0;col<matrix[0].length;col++){                if(matrix[row][col]=='1'){                    height[col]++;                }                else{                    height[col]=0;                }            }            res=Math.max(res,largestInLine(height));        }        return res;    }    public int largestInLine(int[] height) {        if(height == null || height.length == 0) return 0;        int len = height.length;        Stack<Integer> s = new Stack<Integer>();        int maxArea = 0;        for(int i = 0; i <= len; i++){            int h = (i == len ? 0 : height[i]);            if(s.isEmpty() || h >= height[s.peek()]){                s.push(i);            }else{                int tp = s.pop();                maxArea = Math.max(maxArea, height[tp] * (s.isEmpty() ? i : i - 1 - s.peek()));                i--;            }        }        return maxArea;    }