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#include "leetcode.h"
class Solution {
public:
int minDays(vector<vector<int>> &grid) {
int islands = islandCount(grid);
int n = grid.size(), m = grid[0].size();
if (islands > 1 || islands == 0)
return 0;
else {
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
if (grid[i][j]) {
grid[i][j] = 0;
islands = islandCount(grid);
grid[i][j] = 1;
if (islands > 1 || islands == 1)
return 1;
}
}
}
}
return 2;
}
private:
vector<int> dx = {1, -1, 0, 0}, dy = {0, 0, 1, -1};
void dfs(int x, int y, vector<vector<int>> &grid, vector<vector<int>> &vis) {
int n = grid.size(), m = grid[0].size();
vis[x][y] = 1;
for (int a = 0; a < 4; a++) {
int nx = x + dx[a], ny = y + dy[a];
if (nx >= 0 && ny >= 0 && nx < n && ny < m && !vis[nx][ny] &&
grid[nx][ny])
dfs(nx, nx, grid, vis);
}
}
int islandCount(vector<vector<int>> &grid) {
int count = 0, n = grid.size(), m = grid[0].size();
vector<vector<int>> vis(n, vector<int>(m, 0));
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
if (!vis[i][j] && grid[i][j]) {
dfs(i, j, grid, vis);
}
}
}
return count;
}
};
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