Here is my code, it is running on my computer:
const int m = 5;
const int n = 5;
// check whether the agent has visited the cells
int visited[m][n];
const int dx[] = {0, 1, -1, 0};
const int dy[] = {1, 0, 0, -1};
bool is_visited(int x, int y, int mat[m][n]){
if (0 <= x and y >= 0 and x < m and y < n){
if (visited[x][y] == false and mat[x][y] == 1) return true;
else return false;
}
else return false;
}
int COUNT = 0;
unordered_map <int, int> match_query;
void FindConnectedComponents(int mat[m][n]){
// check every unvisited cell in the mat
for (int i = 0; i < m; ++i){
for (int j = 0; j < n; ++j){
if (visited[i][j] == false and mat[i][j] == 1){
queue<pair<int, int> >q;
//store coord of 1
q.push({i,j}); // now q is not empty
// update visited
visited[i][j] = true;
COUNT = 0;
while (!q.empty()){
pair<int, int> temp_q = q.front();
q.pop();
int x = temp_q.first; int y = temp_q.second;
COUNT+=1;
for (int i = 0; i < 4; ++i){
int newX = x + dx[i];
int newY = y + dy[i];
if (is_visited(newX, newY, mat)){
visited[newX][newY] = true;
// continue store newX and newY on q to keep checking
q.push({newX, newY});
}
}
}
cout << COUNT <<" ";
match_query[COUNT]++;
}
}
}
}
The problem is now I want to use a class and the value of m and n is not fixed anymore
now m and should be int m = grid.size(); and int n = grid[0].size();. However, we can easily see that: the compiler immediately throws the error "grid is undeclared ".
class Solution {
/* even if I try:
int m,n;
int visited[m][n]; // ERROR: invalid use of non-static data member 'm'
*/
public:
static constexpr int dx[] = {0,1,-1,0};
static constexpr int dy[] = {1,0,0,-1};
int m = grid.size(); // ERROR
int n = grid[0].size(); // ERROR
int visited[m][n];
bool is_visited(int x, int y, vector<vector<char> >&grid){
if (x >= 0 and x < grid.size() and y >= 0 and y < grid[0].size()){
if (visited[x][y] == false and grid[x][y] =='1' ){
return true;
}
else return false;
}
else return false;
}
int count = 0;
int numIslands(vector<vector<char> >& grid) {
for (int i= 0; i< grid.size(); ++i){
for (int j = 0; i< grid[i].size(); ++j){
if (grid[i][j] == '1' and visited[i][j] == false){
visited[i][j] = true;
queue<pair<int, int> > q;
q.push({i,j});
while (!q.empty()){
pair<int, int> temp_q = q.front();
q.pop(); // delete q after storing it
int x = temp_q.first; int y = temp_q.second;
for (int i = 0; i< 4; ++i){
int newX = x + dx[i];
int newY = y + dy[i];
if (is_visited(newX, newY, grid) ){
visited[newX][newY] = true;
q.push({newX, newY});
}
}
}
}
count += 1;
}
}
return count;
}
};
Can you guys please tell me how can I get the grid size for the m an n variables in order to pass visited that still is global?
