Splay入门题目 [HNOI2002]营业额统计

题目链接：http://www.lydsy.com/JudgeOnline/problem.php?id=1588

这道题貌似很多中做法，我先是用multiset交了一发，然后又写了一发splay。

multiset做法，这个其实就是二分了，只是用set来保持加入一个元素时保持有序

 #include <set>
 #include <map>
 #include <cmath>
 #include <ctime>
 #include <queue>
 #include <stack>
 #include <cctype>
 #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-;
 multiset<int>S;
 multiset<int>::iterator it;
 int main(void)
 {
     #ifndef ONLINE_JUDGE
         freopen("in.txt","r",stdin);
     #endif
     int n;
     while (~scanf ("%d",&n))
     {
         int ans = ;
         S.clear();
         for (int i = ; i < n; i++)
         {
             int x;
             if (scanf ("%d",&x) == EOF)
                 x = ;
             it = S.lower_bound(x);
             if (it == S.begin())
                 ans += abs(*it-x);
             else
             {
                 int s1 = *it;
                 int s2 = *--it;
                 ans +=  min(abs(s1 - x),abs(s2 - x));
             }
             S.insert(x);
         }
         printf("%d\n",ans);
     }
     return ;
 }

splay

 #include <set>
 #include <map>
 #include <cmath>
 #include <ctime>
 #include <queue>
 #include <stack>
 #include <cctype>
 #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-;
 template <class T>
 inline bool scan_d(T &ret)
 {
     char c;
     int sgn;
     if(c=getchar(),c==EOF)
         return ;
     while(c!='-'&&(c<''||c>''))
         c=getchar();
     sgn = (c=='-')?-:;
     ret =(c=='-')?:(c-'');
     while(c=getchar(),c>=''&&c<='')
         ret=ret*+(c-'');
     ret*=sgn;
     return ;
 }
 const int maxn = 1e5+;
 int fa[maxn],son[maxn][],key[maxn],tot,root;

 void addNode(int &r,int father,int k)
 {
     r = ++tot;
     fa[r] = father;
     key[r] = k;
     son[r][] = son[r][] = ;
 }

 void Rotate(int r,int kind)
 {
     int y = fa[r];
     son[y][!kind] = son[r][kind];
     fa[son[r][kind]] = y;
     if (fa[y])
         son[fa[y]][son[fa[y]][]==y] = r;
     son[r][kind] = y;
     fa[r] = fa[y];
     fa[y] = r;
 }
 void splay(int r,int goal)
 {
     while (fa[r] != goal)
     {
         if (fa[fa[r]] == goal)
         {
             Rotate(r,son[fa[r]][] == r);
         }
         else
         {
             int y = fa[r];
             int kind = (son[fa[y]][] == y);
             if (son[y][kind] == r)
             {
                 Rotate(r,!kind);
                 Rotate(r,kind);
             }
             else
             {
                 Rotate(y,kind);
                 Rotate(r,kind);
             }
         }
     }
     if (goal == )
         root = r;
 }
 bool Insert(int k)
 {
     int r = root;
     while (son[r][k > key[r]])
     {
         if (k == key[r])
         {
             splay(r,);
             return false;
         }
         r = son[r][k>key[r]];
     }
     addNode(son[r][k>key[r]],r,k);
     splay(son[r][k>key[r]],);
     return true;
 }
 int get_pre(int r)
 {
     int tmp = son[r][];
     if (tmp == )
         return inf;
     while (son[tmp][])
         tmp = son[tmp][];
     return  key[tmp];
 }
 int get_next(int r)
 {
     int tmp = son[r][];
     if (tmp==)
         return inf;
     while (son[tmp][])
         tmp = son[tmp][];
     return key[tmp] ;
 }
 int main(void)
 {
     #ifndef ONLINE_JUDGE
         freopen("in.txt","r",stdin);
     #endif
     int n;
     while (~scanf ("%d",&n))
     {
         tot = ;
         root = ;
         int ans = ;
         for (int i = ; i < n; i++)
         {
             int x;
             if (scanf ("%d",&x) == EOF)
                 x = ;
             if (i == )
             {
                 ans += x;
                 addNode(root,,x);
             }
             else
             {
                 if (!Insert(x))
                     continue;
                 int l = get_pre(root);
                 int r = get_next(root);
                 ans += min(abs(x-l),abs(x-r));
                 //ans += min(l,r);
             }
         }
         printf("%d\n",ans);
     }
     return ;
 }