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Cod sursa(job #597294)
#include<stdio.h>
#include<algorithm>
#include<vector>
#define maxN 805
#define i64 long long
using namespace std;
FILE*f=fopen("poligon.in","r");
FILE*g=fopen("poligon.out","w");
int n,q,i,j,D[maxN],dx,Nr[maxN];
int bnd,x,y,nrpct,lowerpoints;
double xm,ym;
vector< pair<double,int> >S[maxN];
struct pct{
int x;
int y;
}A[maxN],B[maxN],z;
struct dreapta{
int a;
int b;
i64 c;
}E[maxN];
struct cmp{
inline bool operator () ( const pct &a, const pct &b ) {
if ( a.x != b.x )
return a.x < b.x;
return a.y < b.y;
}
};
inline void citire () {
fscanf(f,"%d %d",&n,&q);
for ( i = 1 ; i <= n ; ++i ){
fscanf(f,"%d %d",&A[i].x,&A[i].y);
B[i] = A[i];
}
}
inline void first () {
sort( B+1, B+n+1, cmp() ); B[0].x = -(1<<29);
for ( i = 1 ; i <= n ; ++i ){
if ( B[i].x != B[i-1].x ){
D[++dx] = B[i].x;
}
}
A[n+1] = A[1];
for ( i = 1 ; i <= n ; ++i ){
E[i].a = A[i+1].y - A[i].y;
E[i].b = A[i].x - A[i+1].x;
E[i].c = 1LL*A[i+1].x*A[i].y - 1LL*A[i+1].y*A[i].x;
if ( E[i].b < 0 ){
E[i].a *= (-1); E[i].b *= (-1); E[i].c *= (-1);
}
}
for ( i = 1 ; i < dx ; ++i ){
S[i].push_back(make_pair(-1,-1));
for ( j = 1 ; j <= n ; ++j ){
if ( A[j].x == A[j+1].x ) continue;
if ( min(A[j].x,A[j+1].x) <= D[i] && D[i+1] <= max(A[j].x,A[j+1].x) ){
xm = (double)(D[i+1]+D[i]) / 2;
ym = (double)(-E[j].c - 1LL*E[j].a * xm) / E[j].b;
S[i].push_back(make_pair(ym,j)); ++Nr[i];
}
}
sort( S[i].begin(),S[i].end() );
}
}
inline int cb1 ( int X ){
int pas = 1 << 10,i;
for ( i = 0 ; pas ; pas >>= 1 ){
if ( i + pas <= dx && D[i+pas] <= X )
i += pas;
}
return i;
}
inline i64 det( pct a, pct b , pct c ){
if ( a.x > c.x ){
pct aux; aux = a; a = c; c = aux;
}
i64 Det = 1LL*(a.x - c.x) * (b.y - c.y) + 1LL*(a.y - c.y) * (c.x - b.x);
return Det;
}
inline int cb2 () {
int pas = 1 << 10,i;
for ( i = 0 ; pas ; pas >>= 1 ){
if ( i + pas <= Nr[bnd] )
if ( det( A[S[bnd][i+pas].second] , z , A[S[bnd][i+pas].second + 1] ) <= 0 )
i += pas;
}
return i;
}
inline void solve () {
while ( q-- ){
fscanf(f,"%d %d",&x,&y); z.x = x; z.y = y;
if ( x < D[1] || x > D[dx] ){
continue;
}
bnd = cb1(x);
lowerpoints = cb2();
if ( lowerpoints && ((lowerpoints & 1) || ( !det(A[S[bnd][lowerpoints].second],z,A[S[bnd][lowerpoints].second+1]) )) )
++nrpct;
}
fprintf(g,"%d\n",nrpct);
}
int main () {
citire();
first();
solve();
fclose(f);
fclose(g);
return 0;
}