Codeforce 220 div2

D

　　插入: 在当前指针位置sz处插入一个1,col[sz]记录插入的内容,sz++;

　　删除i: 找到第i个1的位置,赋为0;

　　于是转化为一个维护区间和的问题;

　　trick:

　　如果是依次删除a[0],a[1]...a[k], 那么对应的删除操作应该为 a[0],a[1]-1,a[2]-2...a[k]-k,要把前面删掉的算进去;

　　

 #define maxn 1000100
 int bit[maxn],a[maxn],n,m,col[maxn],sz;
 int lowbit(int x){return x&(-x);}
 void ins(int pos,int c,int v){
     col[pos]=c;
 //    printf("ins %d at %d c=%d\n",v,pos,c);
     for (int cur=pos ; cur<=n ; cur+=lowbit(cur))
         bit[cur]+=v;
 }
 int query(int x){
     int res=;
     for (int i=x ; i> ; i-=lowbit(i)) res += bit[i];
     return res;
 }
 int sum(int l,int r){
     return query(r)-query(l-);
 }
 void del(int pos){
     int l=,r=sz;
     while (l<r){
         if(query(mid)>=pos) r=mid;
         else l=mid+;
     }
 //    printf("del:%dth at %d\n",pos,l);
     ins(l,col[l],-);
 }
 int binsearch(int l,int r,int len){
     while (l<=r){
         if (a[mid]>len) r=mid-;
         else l=mid;
         if (l+>=r){
             if (a[r]<=len) return r;
             if (a[l]<=len) return l;
             return -;
         }
     }
     return -;
 }
 int main(){
 //    freopen("test","r",stdin);
     scanf("%d%d",&n,&m);
     rep(i,m) scanf("%d",&a[i]);
     sz = ;
     rep(i,n){
         int o;
         scanf("%d",&o);
 //        printf("o=%d\n",o);
         if (o==-){
             int len = sum(,sz);
             int k = binsearch(,m-,len);
 //            printf("len=%d k=%d\n",len,k);
             for (int i= ; i<=k ; i++ ) del(a[i]-i);
         }else{
             ins(++sz,o,);
         }
     }
     if (query(sz)){
         for (int i= ; i<=sz ; i++ ) if(sum(i,i)) printf("%d",col[i]);
     }
     else
         printf("Poor stack!\n");
     return ;
 }

E

　　显然把坐标变为(x+y,x-y),生长的线段都是平行坐标轴的,会让问题简单很多;

　　然后考虑某时间t,有若干线段,如果能判断这些线段是否构成矩形,就能二分t来确定答案;

　　判断:

　　预处理处当前时间产生的所有线段;

　　枚举横线作为矩形上边,将所有与它相交的竖线插入树状数组,

　　枚举,下边,回答询问,>=2说明围成矩形;

　　这是O(n^3)做法,可以通过排序,逐个插入等办法优化成O(n^2)的.

　　

 #define rep(i,n) for(int i=0 ; i<(n) ; i++)
 #define mid ((l+r)>>1)
 #define ls ((rt<<1))
 #define rs ((rt<<1)+1)
 #define maxn 2020
 #define INF 2000100
 struct node{
     int x,y;
 };node red[maxn],blue[maxn];
 struct line{
     int p,l,r;
 };vector<line>lx[maxn],ly;

 int n,m,bit[maxn][maxn];
 vector<int>X,Y;
 bool cmpb(node a,node b){
     return (a.x==b.x)?(a.y<b.y):(a.x<b.x);
 }
 bool cmpr(node a,node b){
     return (a.y==b.y)?(a.x<b.x):(a.y<b.y);
 }
 void input(){
     scanf("%d%d",&n,&m);
     int x,y;
     rep(i,n) {
         scanf("%d%d",&x,&y);
         blue[i]=(node){x+y,x-y};
         X.push_back(blue[i].x);
     }
     rep(i,m) {
         scanf("%d%d",&x,&y);
         red[i]=(node){x+y,x-y};
         Y.push_back(red[i].y);
     }
     sort(blue,blue+n,cmpb);
     sort(red,red+m,cmpr);
 }
 void compress(){
     sort(X.begin(),X.end());
     sort(Y.begin(),Y.end());
     X.erase(unique(X.begin(),X.end()),X.end());
     Y.erase(unique(Y.begin(),Y.end()),Y.end());
 }
 int findlft(vector<int>a,int var){
     int l=,r=(int)a.size()-;
     while (l<r){
         if (a[mid]>=var) r=mid;
         else l=mid+;
     }
     return a[l]>=var?l:INF;
 }
 int findrgt(vector<int>a,int var){
     int l=,r=(int)a.size()-;
     while (l<=r){
         if (a[mid]<=var) l=mid;
         else r=mid-;
         if (l+>=r){
             if (a[r]<=var) return r;
             if (a[l]<=var) return l;
             return -INF;
         }
     }
     return -INF;
 }
 int lowbit(int x) {return x&(-x);}
 int query(int y,int x){
     int res=;
     for ( ; x> ; x-=lowbit(x)) {
         res += bit[y][x];
         if (bit[y][x]<) while();
     }
     return res;
 }
 int sum(int y,int l,int r){
     if (l>r) return ;
     return query(y,r)-query(y,l-);
 }
 void ins(int y,int x,int v){
     for ( ; x<maxn ; x+=lowbit(x) ) {
         bit[y][x]+=v;
         if (bit[y][x]<) while();
     }
 }
 bool vis[maxn];
 void addline(int idx){
     for (int i=ly[idx].l ; i<=ly[idx].r ; i++ )
         ins(i,ly[idx].p,);
     vis[idx]=true;
 }
 void delline(int idx){
     for (int i=ly[idx].l ; i<=ly[idx].r ; i++ )
         ins(i,ly[idx].p,-);
     vis[idx]=false;
 }
 bool check(int t){
     ly.clear();
     rep(i,(int)Y.size()) lx[i].clear();
     rep(i,n){//find ly;
         int x = lower_bound(X.begin(),X.end(),blue[i].x)-X.begin()+;
         int l = blue[i].y-*t;
         int r = blue[i].y+*t;
         while (i+<n){
             int tmp = blue[i+].y-*t;
             if (blue[i+].x==blue[i].x && l<=tmp && tmp<=r){
                 r = blue[i+].y+*t;
                 i++;
             }else break;
         }
         l = findlft(Y,l);
         r = findrgt(Y,r);
         if (l<=r) ly.push_back((line){x,l,r});
     }
     rep(i,m){//find lx;
         int y = lower_bound(Y.begin(),Y.end(),red[i].y)-Y.begin();
         int l = red[i].x-*t;
         int r = red[i].x+*t;
         while (i+<m){
             int tmp = red[i+].x-*t;
             if (red[i+].y==red[i].y && l<=tmp && tmp<=r){
                 r = red[i+].x+*t;
                 i++;
             }else break;
         }
         l = findlft(X,l)+;
         r = findrgt(X,r)+;
         if (l<r) lx[y].push_back((line){y,l,r});
     }
     rep(i,(int)Y.size()){
         rep(j,(int)ly.size()) if (vis[j] && !(ly[j].l<=i && i<=ly[j].r)) delline(j);
         rep(j,(int)ly.size()) if (!vis[j] && ly[j].l<=i && i<=ly[j].r) addline(j);

         rep(j,(int)lx[i].size()){
             line cur = lx[i][j];
             if (sum(i,cur.l,cur.r)<) continue;
             rep(k,i) rep(x,(int)lx[k].size()){
                 int l = max(cur.l,lx[k][x].l);
                 int r = min(cur.r,lx[k][x].r);
                 if (sum(i,l,r)>= && sum(k,l,r)>=) {
                     rep(i,(int)ly.size()) if(vis[i]) delline(i);
                     return true;
                 }
             }
         }
     }
     rep(i,(int)ly.size()) if(vis[i]) delline(i);
     return false;
 }
 int binsearch(int l,int r){
     while (l<r){
         if (check(mid)) r=mid;
         else l=mid+;
     }
     return check(l)?l:;
 }
 int main(){
 //    freopen("test","r",stdin);
     input();
     compress();
     int ans = binsearch(,INF);
     if (!ans) printf("Poor Sereja!\n");
     else printf("%d\n",ans);
     return ;
 }