Codeforces Beta Round #32 (Div. 2, Codeforces format)

Codeforces Beta Round #32 (Div. 2, Codeforces format)

http://codeforces.com/contest/32

A

 #include<bits/stdc++.h>
 using namespace std;
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 #define sqr(x) ((x)*(x))
 #define pb push_back
 #define maxn 1000005
 typedef long long ll;
 typedef unsigned long long ull;
 /*#ifndef ONLINE_JUDGE
         freopen("1.txt","r",stdin);
 #endif */

 int n,m;
 int a[];

 int main(){
     #ifndef ONLINE_JUDGE
       //  freopen("1.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     cin>>n>>m;
     int ans=;
     for(int i=;i<=n;i++) cin>>a[i];
     for(int i=;i<=n;i++){
         for(int j=;j<=n;j++){
             if(i!=j&&abs(a[i]-a[j])<=m){
                 ans++;
             }
         }
     }
     cout<<ans<<endl;
 }

B

模拟

 #include<bits/stdc++.h>
 using namespace std;
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 #define sqr(x) ((x)*(x))
 #define pb push_back
 #define maxn 1000005
 typedef long long ll;
 typedef unsigned long long ull;
 /*#ifndef ONLINE_JUDGE
         freopen("1.txt","r",stdin);
 #endif */

 int n,m;
 int a[];

 int main(){
     #ifndef ONLINE_JUDGE
       //  freopen("1.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     string str;
     cin>>str;
     for(int i=;i<str.length();i++){
         if(str[i]=='.'){
             cout<<;
         }
         else{
             if(str[i+]=='.'){
                 cout<<;
             }
             else{
                 cout<<;
             }
             i++;
         }
     }
 }

C

水题

 #include<bits/stdc++.h>
 using namespace std;
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 #define sqr(x) ((x)*(x))
 #define pb push_back
 #define maxn 1000005
 typedef long long ll;
 typedef unsigned long long ull;
 /*#ifndef ONLINE_JUDGE
         freopen("1.txt","r",stdin);
 #endif */

 int main(){
     #ifndef ONLINE_JUDGE
       //  freopen("1.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     ll n,m,s;
     cin >> n  >> m >> s;
     ll w = (n - ) / s;
     ll h = (m - ) / s;
     ll cnt = (w + ) * (h + );
     ll a = min (s -  , (m - ) % s);
     ll b = min (s -  , (n - ) % s);
     cout << (a + ) * (b + ) * cnt << endl;
     return ;
 }

D

模拟

 #include<bits/stdc++.h>
 using namespace std;
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 #define sqr(x) ((x)*(x))
 #define pb push_back
 #define maxn 1000005
 typedef long long ll;
 typedef unsigned long long ull;
 /*#ifndef ONLINE_JUDGE
         freopen("1.txt","r",stdin);
 #endif */

 string a[];
 int n,m,k;
 int main(){
     #ifndef ONLINE_JUDGE
       //  freopen("1.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     cin>>n>>m>>k;
     for (int i=;i<n;i++) cin>>a[i];
     for (int r=;r<n;r++)
         for (int i=r;i<n-r;i++)
             for (int j=r;j<m-r;j++)
                 if (a[i][j]=='*'&&a[i+r][j]=='*'&&a[i][j+r]=='*'&&a[i-r][j]=='*'&&a[i][j-r]=='*'){
                     k--;
                     if (!k){
                         cout<<i+<<" "<<j+<<" "<<i-r+<<" "<<j+<<" "<<i+r+<<" "<<j+<<" "<<i+<<" "<<j-r+<<" "<<i+<<" "<<j+r+<<endl;
                         return ;
                     }
                 }
     cout<<-<<endl;
 }

E

几何

先判断AB是否可以直接相连，不能的话就做A对于镜面的对称点，连接对称点和B,判断这条线段和镜面是否有交点，再判断交点连A是否会经过墙，交点连B是否会经过墙

 #include<bits/stdc++.h>
 using namespace std;
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 #define sqr(x) ((x)*(x))
 #define pb push_back
 #define eps 1e-8
 #define PI acos(-1.0)
 #define maxn 1000005
 typedef long long ll;
 typedef unsigned long long ull;

 /*#ifndef ONLINE_JUDGE
         freopen("1.txt","r",stdin);
 #endif */
 int sgn(double x){
     if(fabs(x)<eps) return ;
     if(x<) return -;
     else return ;
 }
 struct Point{
     double x,y;
     Point(){}
     Point(double _x,double _y){
         x=_x;
         y=_y;
     }
     void input(){
         scanf("%lf %lf",&x,&y);
     }
     void output(){
         printf("%.2f %.2f\n",x,y);
     }
     bool operator == (const Point &b)const{
         return sgn(x-b.x) ==  && sgn(y-b.y)== ;
     }
     bool operator < (const Point &b)const{
         return sgn(x-b.x)==?sgn(y-b.y)<:x<b.x;
     }
     Point operator - (const Point &b)const{
         return Point(x-b.x,y-b.y);
     }
     //叉积
     double operator ^ (const Point &b)const{
         return x*b.y-y*b.x;
     }
     //点积
     double operator * (const Point &b)const{
         return x*b.x+y*b.y;
     }
     //返回长度
     double len(){
         return hypot(x,y);
     }
     //返回长度的平方
     double len2(){
         return x*x+y*y;
     }
     //返回两点的距离
     double distance(Point p){
         return hypot(x-p.x,y-p.y);
     }
     Point operator + (const Point &b)const{
         return Point(x+b.x,y+b.y);
     }
     Point operator * (const double &k)const{
         return Point(x*k,y*k);
     }
     Point operator / (const double &k)const{
         return Point(x/k,y/k);
     }

     //计算pa和pb的夹角
     //就是求这个点看a,b所成的夹角
     ///LightOJ1202
     double rad(Point a,Point b){
         Point p=*this;
         return fabs(atan2(fabs((a-p)^(b-p)),(a-p)*(b-p)));
     }
     //化为长度为r的向量
     Point trunc(double r){
         double l=len();
         if(!sgn(l)) return *this;
         r/=l;
         return Point(x*r,y*r);
     }
     //逆时针转90度
     Point rotleft(){
         return Point(-y,x);
     }
     //顺时针转90度
     Point rotright(){
         return Point(y,-x);
     }
     //绕着p点逆时针旋转angle
     Point rotate(Point p,double angle){
         Point v=(*this) -p;
         double c=cos(angle),s=sin(angle);
         return Point(p.x+v.x*c-v.y*s,p.y+v.x*s+v.y*c);
     }
 };

 struct Line{
     Point s,e;
     Line(){}
     Line(Point _s,Point _e){
         s=_s;
         e=_e;
     }
     bool operator==(Line v){
         return (s==v.s)&&(e==v.e);
     }
     //根据一个点和倾斜角angle确定直线，0<=angle<pi
     Line(Point p,double angle){
         s=p;
         if(sgn(angle-PI/)==){
             e=(s+Point(,));
         }
         else{
             e=(s+Point(,tan(angle)));
         }
     }
     //ax+by+c=0;
     Line(double a,double b,double c){
         if(sgn(a)==){
             s=Point(,-c/b);
             e=Point(,-c/b);
         }
         else if(sgn(b)==){
             s=Point(-c/a,);
             e=Point(-c/a,);
         }
         else{
             s=Point(,-c/b);
             e=Point(,(-c-a)/b);
         }
     }
     void input(){
         s.input();
         e.input();
     }
     void adjust(){
         if(e<s) swap(s,e);
     }
     //求线段长度
     double length(){
         return s.distance(e);
     }
     inline double operator * (const Point &p) const {
         return (e - s) * (p - s);
     }
     //返回直线倾斜角 0<=angle<pi
     double angle(){
         double k=atan2(e.y-s.y,e.x-s.x);
         if(sgn(k)<) k+=PI;
         if(sgn(k-PI)==) k-=PI;
         return k;
     }
     //点和直线的关系
     //1 在左侧
     //2 在右侧
     //3 在直线上
     int relation(Point p){
         int c=sgn((p-s)^(e-s));
         if(c<) return ;
         else if(c>) return ;
         else return ;
     }
     //点在线段上的判断
     bool pointonseg(Point p){
         return sgn((p-s)^(e-s))==&&sgn((p-s)*(p-e))<=;
     }
     //两向量平行(对应直线平行或重合)
     bool parallel(Line v){
       //  cout<<sgn((e-s)^(v.e-v.s))<<endl;
         return sgn((e-s)^(v.e-v.s))==;
     }
     //两线段相交判断
     //2 规范相交
     //1 非规范相交
     //0 不相交
     int segcrossseg(Line v){
         int d1=sgn((e-s)^(v.s-s));
         int d2=sgn((e-s)^(v.e-s));
         int d3=sgn((v.e-v.s)^(s-v.s));
         int d4=sgn((v.e-v.s)^(e-v.s));
         if((d1^d2)==-&&(d3^d4)==-) return ;
         return (d1==&&sgn((v.s-s)*(v.s-e))<=||
                 d2==&&sgn((v.e-s)*(v.e-e))<=||
                 d3==&&sgn((s-v.s)*(s-v.e))<=||
                 d4==&&sgn((e-v.s)*(e-v.e))<=);
     }
     //直线和线段相交判断
     //-*this line -v seg
     //2 规范相交
     //1 非规范相交
     //0 不相交
     int linecrossseg(Line v){
         int d1=sgn((e-s)^(v.s-s));
         int d2=sgn((e-s)^(v.e-s));
         if((d1^d2)==-) return ;
         return (d1==||d2==);
     }
     //两直线关系
     //0 平行
     //1 重合
     //2 相交
     int linecrossline(Line v){
         if((*this).parallel(v))
             return v.relation(s)==;
         return ;
     }
     //求两直线的交点
     //要保证两直线不平行或重合
     Point crosspoint(Line v){
         double a1=(v.e-v.s)^(s-v.s);
         double a2=(v.e-v.s)^(e-v.s);
         if(a1==a2) return Point(1e9,1e9);
         return Point((s.x*a2-e.x*a1)/(a2-a1),(s.y*a2-e.y*a1)/(a2-a1));
     }
     Point PointtoLine(const Point &p){
         return crosspoint(Line(p,p+(s-e).rotleft()));
     }
     Point SymPoint (const Point &p) {
         return PointtoLine (p) *  - p;
     }
     //点到直线的距离
     double dispointtoline(Point p){
         return fabs((p-s)^(e-s))/length();
     }
     //点到线段的距离
     double dispointtoseg(Point p){
         if(sgn((p-s)*(e-s))<||sgn((p-e)*(s-e))<)
             return min(p.distance(s),p.distance(e));
         return dispointtoline(p);
     }
     //返回线段到线段的距离
     //前提是两线段不相交，相交距离就是0了
     double dissegtoseg(Line v){
         return min(min(dispointtoseg(v.s),dispointtoseg(v.e)),min(v.dispointtoseg(s),v.dispointtoseg(e)));
     }
     //返回点P在直线上的投影
     Point lineprog(Point p){
         return s+(((e-s)*((e-s)*(p-s)))/((e-s).len2()));
     }
     //返回点P关于直线的对称点
     Point symmetrypoint(Point p){
         Point q=lineprog(p);
         return Point(*q.x-p.x,*q.y-p.y);
     }
 };
 ///两点之间，两点和镜子之间，镜子和墙
 int main(){
     #ifndef ONLINE_JUDGE
         freopen("1.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     Point v,p;
     v.input();
     p.input();
     Line w,m,L;
     w.input();
     m.input();
     L.s=v,L.e=p;
     if(L.segcrossseg(w)==){
         if(L.segcrossseg(m)==||L.parallel(m)){
             cout<<"YES"<<endl;
             return ;
         }
     }
     else{
         Point tt=m.symmetrypoint(p);
         if(m.segcrossseg(Line(v,tt))!=){
             Point pp=m.crosspoint(Line(v,tt));
             if(pp.x==1e9&&pp.y==1e9){
                 pp=p;
             }
             Line l1,l2;
             l1.s=v,l1.e=pp;
             l2.s=p,l2.e=pp;
            // cout<<l1.segcrossseg(w)<<" "<<l2.segcrossseg(w)<<endl;
             if(l1.segcrossseg(w)==&&l2.segcrossseg(w)==){
                 cout<<"YES"<<endl;
                 return ;
             }
         }
     }
     cout<<"NO"<<endl;
     return ;
 }