update

src/P1330/P1330.cpp

@@ -1,3 +1,65 @@
+#include <iostream>
+#include <vector>
+#include <queue>
+#include <algorithm>
+
+using ll = long long;
+using std::endl;
+static auto &is = std::cin;
+static auto &os = std::cout;
+
+static const ll max_n = 1e4+5;
+
+static ll n, m, a, b;
+static std::vector<ll> next[max_n];
+static bool vis[max_n];
+static std::queue<ll> q;
+static int colors[max_n];
+static ll color_sum[3];
+void set_color(const ll n,const int color)noexcept{
+    colors[n]=color;
+    color_sum[color]++;
+}
+
+void flush_exit()noexcept{
+    os<<endl;
+    _Exit(0);
+}
+
+void bfs(){
+    for(ll i{1};i<=n;i++){
+        if(vis[i])continue;
+        q.push(i);
+        set_color(i, 1);
+        while(!q.empty()){
+            const auto front = q.front();
+            q.pop();
+
+            for(const auto i:next[front]){
+                if(vis[i]){
+                    if(colors[i]==colors[front]){
+                        os<<"Impossible";
+                        flush_exit();
+                    }
+                    continue;
+                }
+                set_color(i,(colors[front]&1)+1);
+                vis[i]=true;
+                q.push(i);
+            }
+        }
+    }
+}
+
 int main(){
-    
+    is>>n>>m;
+    for(ll i{0};i<m;i++){
+        is>>a>>b;
+        next[a].push_back(b);
+        next[b].push_back(a);
+    }
+
+    bfs();
+    os<<std::min(color_sum[1],color_sum[2]);
+    flush_exit();
 }