public class Solution {
public int islandPerimeter(int[][] grid) {
int isIsland = 0, isCount = 0;
for(int i = 0; i < grid.length; i++) {
for(int j = 0; j <grid[i].length; j++) {
if(grid[i][j] == 1) {
isIsland++; //count the number of island
if(i < grid.length - 1 && grid[i+1][j] == 1) isCount++; // count down neighbours
if(j < grid[i].length - 1 && grid[i][j+1] == 1) isCount++; // count right neighbours
}
}
}
return 4*isIsland - 2*isCount;
}
}
/
loop over the matrix and count the number of islands;
if the current dot is an island, count if it has any right neighbour or down neighbour;
the result is islands 4 - neighbours 2
/
Shawngbk
commented
7 years ago
public class Solution { public int islandPerimeter(int[][] grid) { int isIsland = 0, isCount = 0;
} / loop over the matrix and count the number of islands; if the current dot is an island, count if it has any right neighbour or down neighbour; the result is islands 4 - neighbours 2 /