IOI Railway 分类： ioi 2015-03-30 22:29 34人阅读 评论(0) 收藏

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我只是来贴代码的，题解什么的，去问大神吧【顺便推广uoj】

提交地址：http://uoj.ac/problem/29

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#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<ctime>
#include<iostream>
#include<algorithm>
#include "rail.h"

const int MAXN = 50006,MAXM = 10000005;

int f0 = 0, f1 = 0;
int d0[MAXN] = {0},d1[MAXN] = {0};

struct station
{
    int dis,num;
    station(int dis = 0,int num = 0):dis(dis),num(num){}

}a[MAXN] ,b[MAXN] ;
int al ,bl ;
int *loc,*type;
int pos[MAXM] = {0};


inline void update(int x){pos[loc[x]] = type[x];}

bool cmp(const station &p,const station &q)
{
    return (p.dis<q.dis);
}
void solve_right()
{
    int rr = a[1].num;

    loc[rr] = loc[0] + a[1].dis;
    type[rr] = 2;update(rr);

    for(int i = 2; i <= al ; i++)
    {
        int t = a[i].num , tmp = getDistance(t,rr);

        if(pos[loc[rr]-((d0[rr] + tmp - d0[t])>>1)] == 2)
            {loc[t] = loc[rr] - tmp;type[t] = 1;}
        else
            {loc[rr=t] = loc[0] + a[i].dis;type[t] = 2;}

        update(t);
    }

}
void solve_left()
{
    int ll = b[1].num;

    loc[ll] = loc[f1] - b[1].dis;
    type[ll] = 1;update(ll);

    for(int i = 2; i <= bl ; i++)
    {
        int t = b[i].num, tmp = getDistance(ll,t);

        if(pos[loc[ll]+((d1[ll] + tmp - d1[t])>>1)] == 1)
            {loc[t] = loc[ll] + tmp;type[t]= 2; }
        else
            {loc[ll=t] = loc[f1] - b[i].dis;type[t] = 1;}   

        update(t);  
    }   
}


void findLocation(int n, int first, int array1[],int array2[])
{
    loc = array1, type = array2;

    f0 = 0; loc[f0] = first;
    type[f0] = 1; update(f0);

        if(n==1)return ;

    d0[0] = 0;
    for(int i = 1 ; i < n ; i++)
      d0[i] = getDistance(0,i);

    for(int i = 1 ; i < n ; i++)
      a[i] = station(d0[i], i);

    std::sort(a + 1,a + n,cmp);

    f1 = a[1].num;loc[f1] = loc[0] + a[1].dis;
    type[f1] = 2;update(f1);

    d1[0] = d0[f1];
    for(int i = 1 ; i < n ; i++)
      d1[i] = (i!=f1)?getDistance(f1,i):0;

    for(int i = 1; i < n ; i++)
      if(i != f1 && d1[i] < d1[0] && d0[i] == d0[f1] + d1[i])
      {
         loc[i] = loc[f1] - d1[i];
         type[i] = 1;update(i);     
      }


    al =0 ,bl = 0;
    for(int i = 1 ; i < n ; i++)
      if(type[i] == 0)
        if(d0[i] != d0[f1] + d1[i]) 
           a[++al] = station(d0[i],i);
        else              
           b[++bl] = station(d1[i],i);   

    if(al) {std::sort(a+1, a+al+1, cmp);solve_right();}
    if(bl) {std::sort(b+1, b+bl+1, cmp);solve_left();}

    return;
}

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