[BOJ 13244] Tree

src/week4/BOJ13244/BOJ13244_V1.cpp

@@ -0,0 +1,59 @@
+#include <bits/stdc++.h>
+using namespace std;
+int visited[10][1001];
+vector<vector<vector<int>>> injs;
+vector<bool> isTree;
+int N;
+bool dfs(int here, int num, int prev) {
+    visited[num][here] = 1;
+    for (int next : injs[num][here]) {
+        if (next == prev) continue;
+        if (visited[num][next]) return false;
+        if (!dfs(next, num, here)) return false;
+    }
+
+    return true;
+}
+int main() {
+
+    cin >> N;
+    injs.resize(N,vector<vector<int>>());
+    isTree.resize(N);
+    for (int i = 0; i < N; i++) {
+        int nodes;
+        int inp_num;
+        bool tree_flag = true;
+        cin >> nodes;
+        cin >> inp_num;
+        injs[i].resize(nodes+1);
+        if (inp_num != nodes-1)
+            tree_flag = false;
+       for (int j=0; j<inp_num; j++) {
+           int a,b;
+           cin >> a >> b;
+           injs[i][a].push_back(b);
+           injs[i][b].push_back(a);
+       }
+       if (tree_flag && !dfs(1, i, 0))
+           tree_flag = false;
+
+
+       for (int j=1; j<=nodes; j++) {
+           if (!visited[i][j]) {
+               tree_flag = false;
+               break;
+           }
+       }
+
+       isTree[i] = tree_flag;
+    }
+
+
+    for (int i = 0; i < N; i++) {
+        if (isTree[i])
+            cout << "tree" << '\n';
+        else
+            cout << "graph" << '\n';
+    }
+    return 0;
+}

src/week4/BOJ13244/BOJ13244_V2.cpp

@@ -0,0 +1,57 @@
+#include <bits/stdc++.h>
+using namespace std;
+int N,visited[1001];
+vector<vector<int>> inj;
+vector<bool> ret;
+void dfs(int here) {
+    visited[here] = 1;
+    for (int next : inj[here]) {
+        if (!visited[next]) dfs(next);
+    }
+}
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    cout.tie(NULL);
+
+    cin >> N;
+    for (int i = 0; i < N; i++) {
+        memset(visited, 0, sizeof(visited));
+        int nodes;
+        int inp_num;
+        cin >> nodes >> inp_num;
+        inj.clear();
+        inj.resize(nodes + 1);
+
+        for (int j = 0; j < inp_num; j++) {
+            int a, b;
+            cin >> a >> b;
+            inj[a].push_back(b);
+            inj[b].push_back(a);
+        }
+
+        if (inp_num != nodes - 1) {
+            ret.push_back(false);
+            continue;
+        }
+
+        int cnt = 0;
+        for (int j = 1; j <= nodes; j++) {
+            if (!visited[j]) {
+                dfs(j);
+                cnt++;
+            }
+        }
+        if (cnt != 1) {
+            ret.push_back(false);
+            continue;
+        }
+
+        ret.push_back(true);
+    }
+
+    for (int i = 0; i < N; i++) {
+        if (ret[i]) cout << "tree\n";
+        else cout << "graph\n";
+    }
+}