HDU 4302 Holedox Eating

令我及其伤心的一题啊。比赛的时候想用HASH写，波波写出来果断TLE。

正解：

1.STL，set

2.优先队列

3.线段树树状数组

线段树：

#include<stdio.h>
#include<stdlib.h>
#include<iostream>
#include<string.h>
#include<algorithm>
using namespace std;
#define MAXN 401010
const int inf =  0xFFFFFF;
struct node
{
  int l, r, num, Lm, Rm;
}T[MAXN<<4];

int N, M, L, R, pos;

void build( int l,int r, int root)
{
  int mid = (l + r) / 2;
  T[root].l = l;
  T[root].r = r;
  T[root].Lm = inf;
  T[root].Rm = -inf;
  T[root].num = 0;
  if( l == r )
      return;
  build(l, mid, root << 1 );
  build(mid + 1, r, (root << 1) + 1);
}

void insert( int pos, int root)
{
  int mid = (T[root].l + T[root].r) / 2;
  T[root].num++;
  if( T[root].l ==  T[root].r )
  {
     T[root].Lm = T[root].l;
     T[root].Rm = T[root].r;
     return;    
  }
  if( pos > mid )
      insert( pos, (root << 1) + 1);
  else
      insert( pos,  root << 1 );
  T[root].Lm = T[root<<1].Lm < T[(root<<1)+1].Lm ? T[root<<1].Lm : T[(root<<1)+1].Lm;
  T[root].Rm = T[root<<1].Rm > T[(root<<1)+1].Rm ? T[root<<1].Rm : T[(root<<1)+1].Rm;  
}

void query( int p, int root)
{
   int mid = (T[root].l + T[root].r)/2;
   if( T[root].l == T[root].r )
   {
       if( pos == T[root].r && T[root].num > 0)
          R = pos;
       return;
   }
   if( p > mid )
   { 
      if( T[root*2].num )
      L = T[root*2].Rm;
      query( p, (root << 1) + 1);          
   }
   else
   {
      if( T[root*2+1].num )
      R = T[root*2+1].Lm;
      query( p, root << 1 );   
       
   }  
}

void del(int pos, int root )
{
  int mid = (T[root].l + T[root].r) / 2;
  if( T[root].num != 0 )
     T[root].num--;
  if( T[root].l ==  T[root].r )
  {
     if( T[root].num == 0 )
     {
      T[root].Lm = inf;
      T[root].Rm = -inf;
     }
     return;    
  }
  if( pos > mid )
      del(pos, (root << 1) + 1);
  else
      del(pos, root << 1 );
  T[root].Lm = T[root<<1].Lm < T[(root<<1)+1].Lm ? T[root<<1].Lm : T[(root<<1)+1].Lm;
  T[root].Rm = T[root<<1].Rm > T[(root<<1)+1].Rm ? T[root<<1].Rm : T[(root<<1)+1].Rm;               
}

int main( )
{
   int Tn, a, b,dir,steps,f;
   scanf("%d",&Tn);
   int cnt = 1;
   while(Tn--)  
   {
      scanf("%d%d",&N,&M);
      long long ans = 0;
      build(1,N+2,1);
      ans = 0;
      pos = 1;
      dir = 1;
      for( int i= 1; i <= M; i++)
      {
          scanf("%d",&a);
          if( a == 0 )
          {
              scanf("%d",&b);
              b++;
              insert(b, 1);
          }
          else
          {   
              L = inf;
              R = -inf;
              query(pos,1);
              if( L == inf && R == -inf )
                  continue;
              int x1 = abs(L - pos);
              int x2 = abs(R - pos);
              /*郁闷啊。这样写就一直wa... 
              if( x1 < x2 )
              {
                  f = L;
                  steps = x1;
              }
              else 
              {
                  f = R;
                  steps = x2;     
              }
              */
              steps = min(x1,x2);
              if( steps != 0 )
              {
                 ans += steps;
                 if( x1 == x2 )
                 {
                    if( dir == 1 )
                        pos = R;
                    else
                        pos = L;
                            
                 }
                 else if( x1 > x2 )
                 {
                    if( dir == 1 )
                        pos = R;
                    else
                    {
                        pos = R; 
                        dir = 1;
                    }    
                 }
                 else 
                 { 
                     if( dir == -1 )
                         pos = L;
                     else
                     {
                         pos = L;
                         dir = -1;
                     }     
                      
                 }
          
              }
              del(pos,1);
          }
                        
      }
      printf("Case %d: %I64d\n",cnt++,ans);    
             
   }
    
     
}