poj 3670(LIS)

 // File Name: 3670.cpp
 // Author: Missa_Chen
 // Created Time: 2013年07月08日 星期一 21时15分34秒

 #include <iostream>
 #include <string>
 #include <algorithm>
 #include <cstdio>
 #include <cstring>
 #include <cmath>
 #include <queue>
 #include <map>
 #include <stack>
 #include <set>
 #include <cstdlib>
 #include <vector>
 #include <time.h>

 using namespace std;

 #define LL long long
 const int inf = 0x3f3f3f3f;
 const int maxn = 3e4 + ;
 int a[maxn], dp[maxn], D[maxn], len, n;
 //dp[i]表示以第i个元素为子序列最后一个元素的LIS长度。
 //D[len]表示上升子序列长度为len的最后一个元素。
 int LIS()
 {
     len = ;
     memset(dp, , sizeof(dp));
     memset(D, , sizeof(D));
     int ret = ;
     for (int i = ; i <= n; ++i)
     {
         if (a[i] >= D[len])
         {
             dp[i] = len + ;
             D[++len] = a[i];
         }
         else
         {
             int low = , high = len, tmp = ;
             while (low <= high)
             {
                 int mid = (low + high) >> ;
                 if (D[mid] <= a[i])
                 {
                     tmp = mid;
                     low = mid + ;
                 }
                 else
                     high = mid - ;
             }
             dp[i] = tmp + ;
             D[tmp + ] = a[i];
         }
         ret = max(ret, dp[i]);
     }
     return ret;
 }
 int main()
 {
     while (~scanf("%d",&n))
     {
         for (int i = ; i <= n; ++i)
             scanf("%d", &a[i]);
         int ans = LIS();
         reverse(a + , a + n + );
         ans = max(ans, LIS());
         printf("%d\n", n - ans);
     }
     return ;
 }