lanqiao3513 岛屿个数

14lanqiao/test6.cpp

@@ -0,0 +1,84 @@
+// lanqiao3513 岛屿个数
+#include<bits/stdc++.h>
+using namespace std;
+const int N = 1e2 + 10;
+int t, n, m, ans, flag;
+char g[N][N];
+bool vis[N][N];
+int dx[] = {0, 0, 1, -1}, dy[] = {1, -1, 0, 0}; // 搜岛屿连通块的方向数组
+int dx1[] = {0, 0, 1, -1, 1, 1, -1, -1}, dy1[] = {1, -1, 0, 0, 1, -1, 1, -1}; // 搜外海的方向数组
+
+// 搜索独立岛屿-连通块
+void dfs_land(int x, int y){
+    for(int i = 0; i < 4; i++){
+        int bx = x + dx[i], by = y + dy[i];
+        if(bx < 1 || bx > n || by < 1 || by > m) continue;
+        if(vis[bx][by] || g[bx][by] == '0') continue;
+        vis[bx][by] = 1;
+        dfs_land(bx, by);
+    }
+}
+
+// 搜索外海-独立岛屿(非内环岛)
+void dfs_sea(int x, int y){
+    if(x == 0 || x == n + 1 || y == 0 || y == m + 1){
+        flag = true;
+        return;
+    }
+    for(int i = 0; i < 8; i++){
+        int bx = x + dx1[i], by = y + dy1[i];
+        if(bx < 0 || bx > n + 1 || by < 0 || by > m + 1) continue;
+        if(vis[bx][by] || g[bx][by] == '1') continue;
+        vis[bx][by] = 1;
+        dfs_sea(bx, by);
+    }
+}
+
+int main(){
+    cin >> t;
+    while(t--){
+        cin >> n >> m;
+        for(int i = 0; i <= n + 1; i++){
+            for(int j = 0; j <= m + 1; j++){
+                if(i == 0 || i == n + 1 || j == 0 || j == m + 1) g[i][j] = '0'; // 外海
+                else cin >> g[i][j];
+            }
+        }
+        ans = 0;
+        // 查找岛屿连通块
+        memset(vis, 0, sizeof vis);
+        vector<pair<int, int>> vec;
+        for(int i = 1; i <= n; i++){
+            for(int j = 1; j <= m; j++){
+                if(g[i][j] == '1' && !vis[i][j]){
+                    vis[i][j] = 1;
+                    vec.push_back({i, j}); // 记录连通块的点
+                    dfs_land(i, j);
+                }
+            }
+        }
+        for(auto it:vec){
+            memset(vis, 0, sizeof vis);
+            flag = false;
+            dfs_sea(it.first, it.second);
+            if(flag) ans++;
+        }
+        cout << ans << endl;
+    }
+    return 0;
+}
+/* samples -> 1 3
+2
+5 5
+01111
+11001
+10101
+10001
+11111
+5 6
+111111
+100001
+010101
+100001
+111111
+*/