HDU5141--LIS again （LIS变形）

题意一个序列的LIS为MAX， 求连续子序列的LIS为MAX的个数。

先求出LIS，记录以a[i]结尾的LIS的长度，以及LIS起始位置（靠右的起始位置）。

然后线性扫一遍，，线段树与树状数组的差距还是蛮大的，，线段树900+MS，险些超时，而树状数组仅仅400+MS

代码里注释部分为线段树做法。

 #include <set>
 #include <map>
 #include <cmath>
 #include <ctime>
 #include <queue>
 #include <stack>
 #include <cstdio>
 #include <string>
 #include <vector>
 #include <cstdlib>
 #include <cstring>
 #include <iostream>
 #include <algorithm>
 using namespace std;
 typedef unsigned long long ull;
 typedef long long ll;
 const int inf = 0x3f3f3f3f;
 const double eps = 1e-;
 const int maxn = 1e5+;
 int seg[maxn<<],pt[maxn<<],a[maxn],vec[maxn],idx,n;
 int pos1[maxn],pos2[maxn];
 void hash_()
 {
     sort(vec,vec+idx);
     idx = unique(vec,vec+idx) - vec;
     for (int i = ; i < n ;i++)
         a[i] = lower_bound(vec,vec+idx,a[i]) - vec + ;
 }
 int ans,pp;
 /*
 void update(int l,int r,int pos,int x,int val,int s)
 {
     if (l == r)
     {
         if (val == seg[pos] && s > pt[pos])
             pt[pos] = s;
         if (val > seg[pos])
         {
             pt[pos] = s;
             seg[pos] = val;
         }
         return ;
     }
     int mid = (l + r) >> 1;
     if (x <= mid)
         update(l,mid,pos<<1,x,val,s);
     else
         update(mid+1,r,pos<<1|1,x,val,s);
     seg[pos] = max(seg[pos<<1],seg[pos<<1|1]);
     if (seg[pos<<1] > seg[pos<<1|1])
         pt[pos] =pt[pos<<1];
     if (seg[pos<<1] < seg[pos<<1|1])
         pt[pos] = pt[pos<<1|1];
     if (seg[pos<<1] == seg[pos<<1|1])
         pt[pos] = max(pt[pos<<1],pt[pos<<1|1]);
 }
 void query(int l,int r,int pos,int ua,int ub)
 {
     if (ub < ua)
         return ;
     if (ua <= l && ub >= r)
     {
         if (ans < seg[pos])
         {
             ans = seg[pos];
             pp = pt[pos];
         }
         if (ans == seg[pos] && pp < pt[pos])
             pp = pt[pos];
         return ;
     }
     int mid = (l + r) >> 1;
     if (ua <= mid)
         query(l,mid,pos<<1,ua,ub);
     if (ub > mid)
         query(mid+1,r,pos<<1|1,ua,ub);
 }*/
 inline int lowbit (int x)
 {
     return x & -x;
 }
 int c[][maxn];
 void add(int x,int d,int s)
 {
     while (x <= idx)
     {
         if (c[][x] < d)
         {
             c[][x] = d;
             c[][x] = s;
         }
         if (c[][x] == d && c[][x] < s)
         {
             c[][x] = s;
         }
         x += lowbit(x);
     }
 }
 void query(int x)
 {
     while (x)
     {
         if (ans < c[][x])
         {
             pp = c[][x];
             ans = c[][x];
         }
         if (ans == c[][x] && pp < c[][x])
         {
             pp = c[][x];
         }
         x -= lowbit(x);
     }
 }
 int dp[maxn];
 int main(void)
 {
     #ifndef ONLINE_JUDGE
         freopen("in.txt","r",stdin);
     #endif
     while (~scanf ("%d",&n))
     {
         //memset(seg,0,sizeof(seg));
         //memset(pt,0,sizeof(pt));
         memset(c,,sizeof(c));
         idx = ;
         for (int i = ; i < n; i++)
         {
             scanf("%d",a+i);
             vec[idx++] = a[i];
         }
         hash_();
         int LIS = ;
         for (int i = ; i < n; i++)
         {
             ans = ;
             //query(1,n,1,1,a[i]-1);
             query(a[i]-);
             dp[i] = ans + ;
             if (ans == )
                 pos1[i] = i;
             else
                 pos1[i] = pp;
            // update(1,n,1,a[i],dp[i],pos1[i]);
            add(a[i],dp[i],pos1[i]);
             LIS = max(dp[i],LIS);
         }
         int pre = n;
         for (int i = n -; i >= ; i--)
         {
             if (dp[i] != LIS)
                 continue;
             pos2[i] = pre-;
             pre = i;
         }
         ll cnt = ;
         for (int i = ; i < n; i++)
         {
             if (dp[i] != LIS)
                 continue;
             cnt += (ll)(pos1[i] + ) * (pos2[i]+-i);
         }
         printf("%I64d\n",cnt);
     }
     return ;
 }