From http://www.cnblogs.com/d-e-v-i-l/p/5434713.html

SDUSTOJ/1796_cnblogs.cpp

@@ -0,0 +1,128 @@
+/* ***********************************************
+Author        :devil
+Created Time  :2016/4/26 13:11:52
+************************************************ */
+#include <cstdio>
+#include <cstring>
+#include <iostream>
+#include <algorithm>
+#include <vector>
+#include <queue>
+#include <set>
+#include <map>
+#include <string>
+#include <cmath>
+#include <stdlib.h>
+using namespace std;
+const int N=100005;
+int n,a[N],b[N],tree[N<<2];
+void build1(int node,int l,int r)
+{
+    if(l==r)
+    {
+        tree[node]=N;
+        return ;
+    }
+    int m=(l+r)>>1;
+    build1(node<<1,l,m);
+    build1(node<<1|1,m+1,r);
+    tree[node]=min(tree[node<<1],tree[node<<1|1]);
+}
+void update1(int node,int l,int r,int p)
+{
+    if(l==r)
+    {
+        tree[node]=b[p];
+        return ;
+    }
+    int m=(l+r)>>1;
+    if(a[p]<=m) update1(node<<1,l,m,p);
+    else update1(node<<1|1,m+1,r,p);
+    tree[node]=min(tree[node<<1],tree[node<<1|1]);
+}
+int query1(int node,int l,int r,int p)
+{
+    if(l>=p) return tree[node];
+    int m=(l+r)>>1,ans;
+    ans=query1(node<<1|1,m+1,r,p);
+    if(p<=m) ans=min(ans,query1(node<<1,l,m,p));
+    return ans;
+}
+void build2(int node,int l,int r)
+{
+    if(l==r)
+    {
+        tree[node]=0;
+        return ;
+    }
+    int m=(l+r)>>1;
+    build2(node<<1,l,m);
+    build2(node<<1|1,m+1,r);
+    tree[node]=max(tree[node<<1],tree[node<<1|1]);
+}
+void update2(int node,int l,int r,int p)
+{
+    if(l==r)
+    {
+        tree[node]=b[p];
+        return ;
+    }
+    int m=(l+r)>>1;
+    if(a[p]<=m) update2(node<<1,l,m,p);
+    else update2(node<<1|1,m+1,r,p);
+    tree[node]=max(tree[node<<1],tree[node<<1|1]);
+}
+int query2(int node,int l,int r,int p)
+{
+    if(r<=p) return tree[node];
+    int m=(l+r)>>1,ans;
+    ans=query2(node<<1,l,m,p);
+    if(p>m) ans=max(ans,query2(node<<1|1,m+1,r,p));
+    return ans;
+}
+int main()
+{
+    //freopen("in.txt","r",stdin);
+    while(~scanf("%d",&n))
+    {
+        int x,flag=1;
+        for(int i=1; i<=n; i++)
+        {
+            scanf("%d",&x);
+            a[x]=i;
+        }
+        for(int i=1; i<=n; i++)
+        {
+            scanf("%d",&x);
+            b[x]=i;
+        }
+        build1(1,1,n);
+        for(int i=n; i>0; i--)
+        {
+            if(a[i]<=b[i]&&b[i]>query1(1,1,n,a[i]))
+            {
+                flag=0;
+                break;
+            }
+            update1(1,1,n,i);
+        }
+        if(!flag)
+        {
+            printf("NO\n");
+            continue;
+        }
+        build2(1,1,n);
+        for(int i=1; i<=n; i++)
+        {
+            if(a[i]>=b[i]&&b[i]<query2(1,1,n,a[i]))
+            {
+                flag=0;
+                break;
+            }
+            update2(1,1,n,i);
+        }
+        if(!flag) printf("NO\n");
+        else printf("YES\n");
+    }
+    return 0;
+}