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leetcode695.cpp
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leetcode695.cpp
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#include <iostream>
#include <vector>
using namespace std;
class Solution {
private:
vector<vector<bool>> visit;
int ans = 0;
bool valid(vector<vector<int>>& grid, int i, int j) {
int row = grid.size();
int col = grid[0].size();
if (i >= row || i < 0)
return false;
if (j >= col || j < 0)
return false;
if (visit[i][j] || grid[i][j] == 0)
return false;
return true;
}
void dfs(vector<vector<int>>& grid, int i, int j, int& sum) {
sum++;
if (sum > ans)
ans = sum;
visit[i][j] = true;
if (valid(grid, i - 1, j))
dfs(grid, i - 1, j, sum);
if (valid(grid, i + 1, j))
dfs(grid, i + 1, j, sum);
if (valid(grid, i, j - 1))
dfs(grid, i, j - 1, sum);
if (valid(grid, i, j + 1))
dfs(grid, i, j + 1, sum);
}
public:
int maxAreaOfIsland(vector<vector<int>>& grid) {
int row = grid.size();
int col = grid[0].size();
visit = vector<vector<bool>>(row, vector<bool>(col, false));
for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++) {
if (grid[i][j] == 0)
continue;
if (visit[i][j])
continue;
int sum = 0;
dfs(grid, i, j, sum);
}
}
return ans;
}
};