delete pics to save space

1.1155.cpp

@@ -0,0 +1,68 @@
+#include<cstdio>
+#include<cstdlib>
+#include<cstring>
+#include<stack>
+#include<vector>
+#include<algorithm>
+using namespace std;
+const int oo=0x3f3f3f3f;
+const int maxn=1005;
+int n;
+int a[maxn],f[maxn],vis[maxn];
+vector<int> G[maxn];
+void dfs(int u,int c)
+{
+	if(vis[u]!=-1&&vis[u]!=c) { printf("0\n"); exit(0); }
+	if(vis[u]!=-1) return;
+	vis[u]=c;
+	for(int i=0;i<G[u].size();i++) dfs(G[u][i],c^1);
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	scanf("%d",&n);
+	for(int i=1;i<=n;i++) scanf("%d",&a[i]);
+	f[n+1]=oo;
+	for(int i=n;i>=1;i--) f[i]=min(f[i+1],a[i]);
+	for(int i=1;i<n;i++)
+		for(int j=i+1;j<n;j++)
+			if(f[j+1]<a[i]&&a[i]<a[j])
+			{
+				G[j].push_back(i);
+				G[i].push_back(j);
+			}
+	memset(vis,-1,sizeof(vis));
+	for(int i=1;i<=n;i++) if(vis[i]==-1) dfs(i,1);
+	stack<int> s1,s2;
+	int now=1;
+	for(int i=1;i<=n;i++)
+	{
+		if(vis[i]==1)
+		{
+			printf("a ");
+			s1.push(a[i]);
+		}
+		else
+		{
+			printf("c ");
+			s2.push(a[i]);
+		}
+		while((s1.size()&&s1.top()==now)||(s2.size()&&s2.top()==now))
+		{
+			if(s1.size()&&s1.top()==now)
+			{
+				printf("b ");
+				s1.pop();
+			}
+			else
+			{
+				printf("d ");
+				s2.pop();
+			}
+			now++;
+		}
+	}
+	return 0;
+}