Submission #272709

#	Time	Username	Problem	Language	Result	Execution time	Memory
272709		MKopchev	Circle selection (APIO18_circle_selection)	C++14	87 / 100	3101 ms	395608 KiB

circle_selection

#include<bits/stdc++.h>
using namespace std;
const int nmax=3e5+42,inf=1e9+42;

struct circle
{
    int x,y,r,id;
};

int n;
circle inp[nmax],sorted_inp[nmax];

bool touch(circle a,circle b)
{
    long long d=1LL*(a.x-b.x)*(a.x-b.x)+1LL*(a.y-b.y)*(a.y-b.y);

    long long mx=a.r+b.r;

    mx=mx*mx;

    return d<=mx;
}

bool cmp(circle a,circle b)
{
    if(a.r!=b.r)return a.r>b.r;
    return a.id<b.id;
}

int outp[nmax];

vector< pair<int/*y*/,int/*id*/> > nodes[nmax*4];
vector<int> prv[nmax*4];
vector<int> nxt[nmax*4];
vector<int> tree[nmax*4];

void update(int node,int l,int r,int pos,circle cur)
{
    //cout<<node<<" -> "<<cur.y<<" "<<cur.id<<endl;
    nodes[node].push_back({cur.y,cur.id});

    if(l==r)return;

    int av=(l+r)/2;

    if(pos<=av)update(node*2,l,av,pos,cur);
    else update(node*2+1,av+1,r,pos,cur);
}
void build(int where,int node,int l,int r)
{
    while(tree[where].size()<=node)tree[where].push_back(0);
    tree[where][node]=r-l+1;

    if(l==r)return;

    int av=(l+r)/2;

    build(where,node*2,l,av);
    build(where,node*2+1,av+1,r);
}
void sub_tree(int where,int node,int l,int r,int pos)
{
    tree[where][node]--;

    if(l==r)return;

    int av=(l+r)/2;

    if(pos<=av)sub_tree(where,node*2,l,av,pos);
    else sub_tree(where,node*2+1,av+1,r,pos);
}
int query(int where,int node,int l,int r,int lq,int rq)
{
    if(tree[where][node]==0)return -1;

    if(l==r)return l;

    int av=(l+r)/2;

    if(lq<=av)
    {
        int mem=query(where,node*2,l,av,lq,min(av,rq));
        if(mem!=-1)return mem;
    }
    if(av<rq)
    {
        int mem=query(where,node*2+1,av+1,r,max(av+1,lq),rq);
        if(mem!=-1)return mem;
    }
    return -1;
}
int find_first(int where,int start)
{
    return query(where,1,0,nodes[where].size()-1,start,nodes[where].size()-1);
}

int pick(int a,int b)
{
    long long sum=a;
    sum=sum+b;

    if(inf<sum)sum=inf;
    if(-inf>sum)sum=-inf;

    return sum;
}
void match(int node,int l,int r,int lq,int rq,circle cur)
{
    if(tree[node].size()==0)return;

    if(tree[node][1]==0)return;

    if(l==lq&&r==rq)
    {
        int y1=pick(cur.y,-2*cur.r);
        int y2=pick(cur.y,2*cur.r);

        int start=lower_bound(nodes[node].begin(),nodes[node].end(),make_pair(y1,0))-nodes[node].begin();

        if(start==nodes[node].size())return;

        start=find_first(node,start);
        /*
        cout<<"circle "<<l<<" "<<r<<" "<<cur.id<<endl;

        for(auto k:nodes[node])
            cout<<k.first<<" "<<k.second<<"\t";cout<<endl;

        cout<<"y1= "<<y1<<" y2= "<<y2<<" start= "<<start<<endl;
        */
        if(start==-1)return;

        vector<int> to_pop={};

        while(start<nodes[node].size()&&nodes[node][start].first<=y2)
        {
            //cout<<"start= "<<start<<" "<<nodes[node][start].second<<" "<<inp[nodes[node][start].second].x<<" "<<inp[nodes[node][start].second].y<<" "<<inp[nodes[node][start].second].r<<endl;

            if(outp[nodes[node][start].second]==0&&touch(inp[nodes[node][start].second],cur))
            {
                //cout<<"touch "<<nodes[node][start].second<<" "<<cur.id<<" "<<endl;

                outp[nodes[node][start].second]=cur.id;
            }

            if(outp[nodes[node][start].second])to_pop.push_back(start);

            start=nxt[node][start];
        }

        for(auto k:to_pop)
        {
            if(0<=prv[node][k])
            {
                nxt[node][prv[node][k]]=nxt[node][k];
            }
            if(nxt[node][k]<nodes[node].size())
            {
                prv[node][nxt[node][k]]=prv[node][k];
            }

            sub_tree(node,1,0,nodes[node].size()-1,k);
        }

        return;
    }

    int av=(l+r)/2;

    if(lq<=av)match(node*2,l,av,lq,min(av,rq),cur);
    if(av<rq)match(node*2+1,av+1,r,max(av+1,lq),rq,cur);
}

int help_x[nmax];

void push(int which)
{
    outp[sorted_inp[which].id]=sorted_inp[which].id;

    int x1=pick(sorted_inp[which].x,-2*sorted_inp[which].r);
    int x2=pick(sorted_inp[which].x,+2*sorted_inp[which].r);

    int le=lower_bound(help_x+1,help_x+n+1,x1)-help_x;
    int ri=upper_bound(help_x+1,help_x+n+1,x2)-help_x;
    ri--;

    //cout<<"le= "<<le<<" ri= "<<ri<<endl;

    if(le>ri)return;

    match(1,1,n,le,ri,sorted_inp[which]);
}
signed main()
{
    scanf("%i",&n);
    for(int i=1;i<=n;i++)
    {
        scanf("%i%i%i",&inp[i].x,&inp[i].y,&inp[i].r);
        inp[i].id=i;
    }

    for(int i=1;i<=n;i++)sorted_inp[i]=inp[i];

    sort(sorted_inp+1,sorted_inp+n+1,cmp);

    for(int i=1;i<=n;i++)help_x[i]=sorted_inp[i].x;

    sort(help_x+1,help_x+n+1);

    for(int i=1;i<=n;i++)
    {
        int pos=lower_bound(help_x+1,help_x+n+1,sorted_inp[i].x)-help_x;

        update(1,1,n,pos,sorted_inp[i]);
    }

    for(int i=1;i<=4*n;i++)
        if(nodes[i].size())
        {
            sort(nodes[i].begin(),nodes[i].end());
            for(int j=0;j<nodes[i].size();j++)
            {
                prv[i].push_back(j-1);
                nxt[i].push_back(j+1);
            }
            build(i,1,0,nodes[i].size()-1);
        }

    for(int i=1;i<=n;i++)
        if(outp[sorted_inp[i].id]==0)
            push(i);

    for(int i=1;i<=n;i++)printf("%i ",outp[i]);printf("\n");
    return 0;
}

Compilation message (stderr)

circle_selection.cpp: In function 'void build(int, int, int, int)':
circle_selection.cpp:51:29: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   51 |     while(tree[where].size()<=node)tree[where].push_back(0);
      |           ~~~~~~~~~~~~~~~~~~^~~~~~
circle_selection.cpp: In function 'void match(int, int, int, int, int, circle)':
circle_selection.cpp:120:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  120 |         if(start==nodes[node].size())return;
      |            ~~~~~^~~~~~~~~~~~~~~~~~~~
circle_selection.cpp:135:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  135 |         while(start<nodes[node].size()&&nodes[node][start].first<=y2)
      |               ~~~~~^~~~~~~~~~~~~~~~~~~
circle_selection.cpp:157:28: warning: comparison of integer expressions of different signedness: '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'} and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  157 |             if(nxt[node][k]<nodes[node].size())
circle_selection.cpp: In function 'int main()':
circle_selection.cpp:221:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  221 |             for(int j=0;j<nodes[i].size();j++)
      |                         ~^~~~~~~~~~~~~~~~
circle_selection.cpp:233:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  233 |     for(int i=1;i<=n;i++)printf("%i ",outp[i]);printf("\n");
      |     ^~~
circle_selection.cpp:233:48: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
  233 |     for(int i=1;i<=n;i++)printf("%i ",outp[i]);printf("\n");
      |                                                ^~~~~~
circle_selection.cpp:195:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  195 |     scanf("%i",&n);
      |     ~~~~~^~~~~~~~~
circle_selection.cpp:198:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  198 |         scanf("%i%i%i",&inp[i].x,&inp[i].y,&inp[i].r);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 15 / 15
• Subtask 4: 23 / 23
• Subtask 5: 30 / 30
• Subtask 6: 0 / 13