19.2.23 [LeetCode 85] Maximal Rectangle
发布时间:2020-12-14 04:23:30 所属栏目:大数据 来源:网络整理
导读: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"],["1","1"],"0"]]Output: 6 题意 找图中由1组成的最大矩形 题解 1 class Solution { 2 publ
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"],["1","1"],"0"]
]
Output: 6
题意找图中由1组成的最大矩形 题解1 class Solution { 2 public: 3 int maximalRectangle(vector<vector<char>>& matrix) { 4 if (matrix.empty())return 0; 5 int m = matrix.size(),n = matrix[0].size(),ans = 0; 6 vector<int>height(n,0),left(n,0),right(n,n); 7 for (int i = 0; i < m; i++) { 8 int s = 0; 9 for (int j = 0; j < n; j++) { 10 if (matrix[i][j] == ‘0‘) { 11 height[j] = 0; 12 left[j] = 0; 13 s = j + 1; 14 } 15 else { 16 left[j] = max(left[j],s); 17 height[j]++; 18 } 19 } 20 int e = n - 1; 21 for (int j = n - 1; j >= 0; j--) { 22 if (matrix[i][j] == ‘0‘) { 23 right[j] = n; 24 e = j - 1; 25 } 26 else { 27 right[j] = min(right[j],e); 28 } 29 } 30 for (int j = 0; j < n; j++) 31 if (matrix[i][j] == ‘1‘) 32 ans = max(ans,(right[j] - left[j] + 1)*height[j]); 33 } 34 return ans; 35 } 36 }; 这题好难的…… 思路是找到三个数组?height[x]?代表从当前行的x索引表示的元素往上数能数到多少连续的1,?left[x]?表示当前行的x索引往左边数能数到多少个连续的height值>=它自己的1,?right[x]?与left相仿(这些计数均包括当前索引且如果当前索引的值为0则这三个数组相应的值无意义) (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |