Count Sub Islands
You are given two m x n binary matrices grid1 and grid2 containing only 0's, representing water, and 1's, representing land. An island is a group of 1's connected 4-directionally: horizontally or vertically. Any cells outside of the grid are considered water cells.
An island in grid2 is considered a sub-island if there is an island in grid1 that contains all the cells that make up this island in grid2.
Return the number of islands in grid2 that are considered sub-islands.
Example 1
1 1 1 0 0 0 1 1 1 1 0 0 0 0 0 1 0 0 0 0 1 1 0 1 1 1 1 1 0 0 0 0 1 1 1 0 1 0 0 0 1 0 1 1 0 0 1 0 1 0
Input
grid1 = [[1,1,1,0,0],[0,1,1,1,1],[0,0,0,0,0],[1,0,0,0,0],[1,1,0,1,1]], grid2 = [[1,1,1,0,0],[0,0,1,1,1],[0,1,0,0,0],[1,0,1,1,0],[0,1,0,1,0]]Output
3There are three islands in grid2 whose land cells are all contained within islands in grid1.
Example 2
1 0 1 0 1 1 1 1 1 1 0 0 0 0 0 1 1 1 1 1 1 0 1 0 1 0 0 0 0 0 1 1 1 1 1 0 1 0 1 0 0 1 0 1 0 1 0 0 0 1
Input
grid1 = [[1,0,1,0,1],[1,1,1,1,1],[0,0,0,0,0],[1,1,1,1,1],[1,0,1,0,1]], grid2 = [[0,0,0,0,0],[1,1,1,1,1],[0,1,0,1,0],[0,1,0,1,0],[1,0,0,0,1]]Output
2There are two islands in grid2 whose land cells are all contained within islands in grid1.
Constraints
- m == grid1.length == grid2.length
- n == grid1[i].length == grid2[i].length
- 1 <= m, n <= 500
- grid1[i][j] and grid2[i][j] are either 0 or 1.