delete pics to save space

history_source/挑战程序设计竞赛/2.5.3.1.cpp

@@ -0,0 +1,43 @@
+#include<cstdio>
+#include<vector>
+using namespace std;
+int n,s;
+vector<int> G[1001];
+int color[1001];
+void init()
+{
+	int a,b;
+	scanf("%d%d",&n,&s);
+	for(int i=0;i<s;i++)
+	{
+		scanf("%d%d",&a,&b);
+		G[a].push_back(b);G[b].push_back(a);
+	}
+}
+bool dfs(int v,int c)
+{
+	color[v]=c;
+	for(int i=0;i<G[v].size();i++)
+	{
+		if(color[G[v][i]]==c) return 0;
+		if(color[G[v][i]]==0&&!dfs(G[v][i],-c)) return 0;
+	}
+	return 1;
+}
+void solve()
+{
+	for(int i=0;i<n;i++)
+		if(color[i]==0)
+			if(!dfs(i,1))
+			{
+				printf("No\n");
+				return;
+			}
+	printf("Yes\n");
+}
+int main()
+{
+	init();
+	solve();
+	return 0;
+}