131 lines
3.4 KiB
C++
131 lines
3.4 KiB
C++
#include <cstdio>
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#include <cstring>
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#include <algorithm>
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using namespace std ;
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#define REP( i , a , b ) for ( int i = a ; i < b ; ++ i )
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#define REV( i , a , b ) for ( int i = a - 1 ; i >= b ; -- i )
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#define FOR( i , a , b ) for ( int i = a ; i <= b ; ++ i )
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#define FOV( i , a , b ) for ( int i = a ; i >= b ; -- i )
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#define CLR( a , x ) memset ( a , x , sizeof a )
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typedef long long LL ;
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const int MAXN = 1005 ;
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const int MAXQ = 2000005 ;
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const int MAXE = 2000005 ;
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const int INF = 0x3f3f3f3f ;
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struct Node {
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int x , y , idx ;
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Node () {}
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Node ( int x , int y , int idx ) : x ( x ) , y ( y ) , idx ( idx ) {}
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void input ( int __ ) {
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scanf ( "%d%d" , &x , &y ) ;
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idx = __ ;
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}
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bool operator < ( const Node &a ) const {
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return x != a.x ? x < a.x : y < a.y ;
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}
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} a[MAXN] ;
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struct Edge {
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int v , c , n ;
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Edge () {}
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Edge ( int v , int c , int n ) : v ( v ) , c ( c ) , n ( n ) {}
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} ;
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Edge E[MAXE] ;
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int H[MAXN] , cntE ;
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int Q[MAXQ] ;
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int head , tail , inq[MAXN] ;
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int d[MAXN] ;
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int n , L ;
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int s , t ;
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void init () {
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cntE = 0 ;
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CLR ( H , -1 ) ;
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}
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void addedge ( int u , int v , int c ) {
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E[cntE] = Edge ( v , c , H[u] ) ;
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H[u] = cntE ++ ;
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E[cntE] = Edge ( u , c , H[v] ) ;
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H[v] = cntE ++ ;
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}
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LL dist ( int i , int j ) {
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LL x = a[i].x - a[j].x ;
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LL y = a[i].y - a[j].y ;
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return x * x + y * y ;
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}
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void spfa () {
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head = tail = 0 ;
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CLR ( inq , 0 ) ;
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CLR ( d , INF ) ;
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d[s] = 0 ;
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Q[tail ++] = s ;
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while ( head != tail ) {
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int u = Q[head ++] ;
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inq[u] = 0 ;
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for ( int i = H[u] ; ~i ; i = E[i].n ) {
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int v = E[i].v ;
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if ( d[v] > d[u] + 1 ) {
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d[v] = d[u] + 1 ;
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if ( !inq[v] ) {
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inq[v] = 1 ;
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Q[tail ++] = v ;
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}
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}
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}
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}
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}
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int cha ( int i , int j , int k ) {
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LL x1 = a[i].x - a[j].x ;
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LL x2 = a[j].x - a[k].x ;
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LL y1 = a[i].y - a[j].y ;
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LL y2 = a[j].y - a[k].y ;
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if ( x1 * y2 - x2 * y1 )
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return 1 ;
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return 0 ;
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}
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void build () {
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LL LLL = ( LL ) L * L ;
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REP ( i , 0 , n )
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REP ( j , i + 1 , n )
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if ( dist ( i , j ) <= LLL ) {
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int ok = 1 ;
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int minx = min ( a[i].x , a[j].x ) ;
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int maxx = max ( a[i].x , a[j].x ) ;
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int miny = min ( a[i].y , a[j].y ) ;
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int maxy = max ( a[i].y , a[j].y ) ;
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for ( int k = i + 1 ; ok && k < j ; ++ k )
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if ( cha ( i , j , k ) == 0 )
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ok = 0 ;
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if ( ok )
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addedge ( i , j , 1 ) ;
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}
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}
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void solve () {
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init () ;
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int x , y ;
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scanf ( "%d%d" , &n , &L ) ;
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a[n].input ( n ) ;
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a[n + 1].input ( n + 1 ) ;
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REP ( i , 0 , n )
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a[i].input ( i ) ;
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n += 2 ;
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sort ( a , a + n ) ;
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build () ;
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REP ( i , 0 , n ) {
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if ( a[i].idx == n - 2 )
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s = i ;
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if ( a[i].idx == n - 1 )
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t = i ;
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}
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spfa () ;
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if ( d[t] == INF )
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printf ( "impossible\n" ) ;
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else
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printf ( "%d\n" , d[t] - 1 ) ;
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}
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int main () {
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int T ;
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scanf ( "%d" , &T ) ;
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while ( T -- )
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solve () ;
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return 0 ;
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}
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