Initial commit

1 files changed, 32 insertions, 0 deletions

diff --git a/04_graph_algorithms/building_roads_1666.cpp b/04_graph_algorithms/building_roads_1666.cpp
new file mode 100644
index 0000000..cf6ac28
--- /dev/null
+++ b/04_graph_algorithms/building_roads_1666.cpp
@@ -0,0 +1,32 @@
+#include <iostream>
+#include <vector>
+
+void visit(size_t i, const std::vector<std::vector<size_t>>& a,
+    std::vector<bool>& c) {
+        if (c[i]) return;
+        c[i] = true;
+        for (auto j : a[i])
+                visit(j, a, c);
+}
+
+int main() {
+        size_t n, m;
+        std::cin >> n >> m;
+        std::vector<std::vector<size_t>> a(n);
+        for (size_t i = 0; i < m; i++) {
+                size_t x, y;
+                std::cin >> x >> y;
+                a[x-1].push_back(y-1);
+                a[y-1].push_back(x-1);
+        }
+
+        std::vector<bool> c(n, false);
+        std::vector<size_t> s;
+        for (size_t i = 0; i < n; i++) {
+                if (c[i]) continue;
+                if (i != 0) s.push_back(i);
+                visit(i, a, c);
+        }
+        std::cout << s.size() << "\n";
+        for (auto x : s) std::cout << "1 " << x+1 << "\n";
+}