delete pics to save space

7.3700.cpp

@@ -0,0 +1,71 @@
+#include<cstdio>
+#include<cstring>
+#include<algorithm>
+using namespace std;
+int n,a[100],lim,up[100],cu,down[100],cd;
+bool dfs(int d)
+{
+	if(cu+cd>lim) return false;
+	if(d==n) return true;
+	int idx=-1;
+	for(int i=0;i<cu;i++) if(a[d]>up[i])
+	{
+		if(idx==-1) idx=i;
+		else if(up[i]>up[idx]) idx=i;
+	}
+	if(idx>-1)
+	{
+		int bk=up[idx];
+		up[idx]=a[d];
+		if(dfs(d+1)) return true;
+		up[idx]=bk;
+	}
+	else
+	{
+		up[cu++]=a[d];
+		if(dfs(d+1)) return true;
+		cu--;
+	}
+	idx=-1;
+	for(int i=0;i<cd;i++) if(a[d]<down[i])
+	{
+		if(idx==-1) idx=i;
+		else if(down[i]<down[idx]) idx=i;
+	}
+	if(idx>-1)
+	{
+		int bk=down[idx];
+		down[idx]=a[d];
+		if(dfs(d+1)) return true;
+		down[idx]=bk;
+	}
+	else
+	{
+		down[cd++]=a[d];
+		if(dfs(d+1)) return true;
+		cd--;
+	}
+	return false;
+}
+inline int solve()
+{
+	for(int i=1;i<=n;i++)
+	{
+		lim=i;
+		cu=cd=0;
+		if(dfs(0)) return i;
+	}
+	return n;
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	while(scanf("%d",&n),n)
+	{
+		for(int i=0;i<n;i++) scanf("%d",&a[i]);
+		printf("%d\n",solve());
+	}
+	return 0;
+}