class Solution {
public:
int islandPerimeter(vector<vector<int>>& grid) {
int squNum = 0 ,log = 0;
for (int i = 0; i<grid.size(); i++) {
for (int j = 0; j<grid[0].size(); j++) {
if (grid[i][j]==1) {
squNum++;
if (i!=0&&grid[i-1][j]==1) {
log+=2;
}
if (j!=grid[0].size()-1&&grid[i][j+1]==1) {
log+=2;
}
}
}
}
return squNum*4-log;
}
};
