OJ-Problems-Source/HDOJ/2337_autoAC.cpp

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#include <iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
using namespace std;
const int N = 1001;
const int M = 1000004;
const int NM = 10001;
struct node
{
int x,y,step;
}que[M],ss,now;
int n,m,nm,sx,sy,ex,ey,maxans,minans,minlen;
int pt[NM][2];
bool flag[N][N];
int dist[N][N];
int dir[4][2] = {{-1,0},{0,-1},{0,1},{1,0}};
int dis(int a,int b,int c,int d)
{
return (abs(a - c) + abs(b - d));
}
void Bfs(int id)
{
ss.x = pt[id][0];
ss.y = pt[id][1];
ss.step = 0;
int i,head,tail;
head = tail = 0;
que[tail ++] = ss;
memset(flag,false,sizeof(flag));
flag[ss.x][ss.y] = true;
while(head != tail)
{
now = que[head ++];
if(head == M)
head = 0;
if(now.step > maxans)
return;
dist[now.x][now.y] = min(dist[now.x][now.y],now.step);
ss = now;
ss.step ++;
for(i = 0;i < 4;i ++)
{
ss.x = now.x + dir[i][0];
ss.y = now.y + dir[i][1];
if(ss.x >= 0 && ss.y >= 0 && ss.x < n && ss.y < m && !flag[ss.x][ss.y])
{
flag[ss.x][ss.y] = true;
que[tail ++] = ss;
if(tail == M)
tail = 0;
}
}
}
}
void init()
{
scanf("%d%d%d",&nm,&n,&m);
scanf("%d%d%d%d",&sx,&sy,&ex,&ey);
maxans = 0x3f3f3f3f;
memset(dist,0x3f,sizeof(dist));
for(int i = 0;i < nm;i ++)
scanf("%d%d",&pt[i][0],&pt[i][1]),maxans = min(maxans,dis(sx,sy,pt[i][0],pt[i][1]));
for(int i = 0;i < nm;i ++)
Bfs(i);
}
bool isok(int x,int y,int cmp)
{
if(x < 0 || y < 0 || x >= n || y >= m)
return false;
else
{
return dist[x][y] >= cmp;
}
}
bool bfs(int lim)
{
ss.x = sx;
ss.y = sy;
ss.step = 0;
memset(flag,false,sizeof(flag));
flag[sx][sy] = true;
int head,tail,i;
head = tail = 0;
que[tail ++] = ss;
while(head != tail)
{
now = que[head ++];
if(head == M)
head = 0;
ss = now;
ss.step ++;
for(i = 0;i < 4;i ++)
{
ss.x = now.x + dir[i][0];
ss.y = now.y + dir[i][1];
if(isok(ss.x,ss.y,lim) && !flag[ss.x][ss.y])
{
if(ss.x == ex && ss.y == ey)
{
minlen = ss.step;
return true;
}
flag[ss.x][ss.y] = true;
que[tail ++] = ss;
if(tail == M)
tail = 0;
}
}
}
return false;
}
void fun()
{
init();
int l,r,mid;
l = 0;r = maxans;
minans = maxans;minlen = dis(ex,ey,sx,sy);
while(l <= r)
{
mid = (l + r)>>1;
if(bfs(mid))
{
minans = mid;
l = mid + 1;
}
else
r = mid - 1;
}
printf("%d %d\n",minans,minlen);
}
int main()
{
int t;
scanf("%d",&t);
while(t --)
{
fun();
}
return 0;
}