1 files changed, 77 insertions, 0 deletions
diff --git a/store/works/life/algorithm-contest-2/solution/3.cpp b/store/works/life/algorithm-contest-2/solution/3.cpp
new file mode 100644
index 0000000..a97e351
--- /dev/null
+++ b/store/works/life/algorithm-contest-2/solution/3.cpp
@@ -0,0 +1,77 @@
+#include <iostream>
+#include <cstdio>
+#include <cstring>
+#include <algorithm>
+#include <vector>
+#include <queue>
+#include <stack>
+#include <set>
+#include <map>
+#include <cmath>
+#include <unordered_map>
+#include <unordered_set>
+#include <string>
+#include <sstream>
+#include <climits>
+#define x first
+#define y second
+#define pub push_back
+#define mp make_pair
+#define ll long long
+using namespace std;
+typedef pair<int, int> PII;
+
+struct node{
+    int x, y;
+    node(){}
+    node(int _x = 0,int _y = 0): x(_x), y(_y){}
+};
+
+int dir[4][2] = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};
+int n;
+vector<string> graph;
+vector<vector<int>> vis;
+
+int solve() {
+    queue<node> Q;
+    for(int i = 0;i < n;++i){
+        for(int j = 0;j < n;++j){
+            if(graph[i][j] == '#') Q.push(node(i,j));
+            vis[i][j] = 0;
+        }
+    }
+    
+    if(Q.size() == n * n || Q.empty()) return -1;
+
+    int dis = 0;
+    while(!Q.empty()){
+        int size = Q.size();
+        while(size-- > 0){
+            node cur = Q.front();
+            Q.pop();
+            for(int i = 0;i < 4;i++){
+                int nextX = cur.x + dir[i][0];
+                int nextY = cur.y + dir[i][1];
+                if(nextX > -1 && nextX < n && nextY > -1 && nextY < n && graph[nextX][nextY] == '.' && !vis[nextX][nextY]){
+                    vis[nextX][nextY] = 1;
+                    Q.push(node(nextX,nextY));
+                }
+            }
+        }
+        if(!Q.empty()) dis += 1;
+    }
+    return dis;
+}
+
+int main(void) {
+    cin >> n;
+    string line;
+    vis.resize(n + 1, vector<int>(n + 1));
+    for (int i = 0; i < n; i++) {
+        cin >> line;
+        graph.push_back(line);
+    }
+
+    cout << solve();
+    return 0;
+}
+\ No newline at end of file