Submission #272751

#	Time	Username	Problem	Language	Result	Execution time	Memory
272751		MKopchev	Circle selection (APIO18_circle_selection)	C++14	87 / 100	3071 ms	373508 KiB

circle_selection

#include<bits/stdc++.h>
using namespace std;
const int nmax=3e5+42,inf=1e9+42,MX=(1<<20)+42;

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

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

bool cmp_y(circle a,circle b)
{
    if(a.y!=b.y)return a.y<b.y;
    return a.id<b.id;
}
int outp[nmax];

vector< pair<int/*y*/,int/*id*/> > nodes[MX];
vector<int> prv[MX];
vector<int> nxt[MX];
vector<int> fenwick[MX];

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);
}

int SZ[nmax];

void upd(int where,int j,int val)
{
    j++;

    while(j<=SZ[nodes[where].size()])
    {
        fenwick[where][j]+=val;
        j=j+(j&(-j));
    }
}
void build(int where)
{
    for(int i=0;i<=SZ[nodes[where].size()];i++)fenwick[where].push_back(0);

    //cout<<where<<" -> "<<fenwick[where].size()<<endl;

    for(int i=0;i<nodes[where].size();i++)
    {
        upd(where,i,1);
    }

    //for(int i=1;i<=nodes[where].size();i++)cout<<fenwick[where][i]<<" ";cout<<endl;
}
void sub_tree(int where,int pos)
{
    upd(where,pos,-1);
}

int query(int where,int pos)
{
    pos++;

    int ret=0;

    while(pos)
    {
        ret=ret+fenwick[where][pos];
        pos=pos-(pos&(-pos));
    }
    return ret;
}

int bits[nmax];

int find_first(int where,int start)
{
    int sum=query(where,start-1);

    //cout<<"find_first "<<where<<" "<<start<<" "<<sum<<endl;

    if(sum==fenwick[where][SZ[nodes[where].size()]])return -1;

    int pos=0;

    for(int j=bits[nodes[where].size()]-1;j>=0;j--)
        if(fenwick[where][pos+(1<<j)]<=sum)
        {
            sum=sum-fenwick[where][pos+(1<<j)];
            pos=pos+(1<<j);
        }

    //cout<<"pos= "<<pos<<endl;

    return pos;
}

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(fenwick[node].size()==0)return;

    if(fenwick[node][SZ[nodes[node].size()]]==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,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],other_sorted[i]=inp[i];

    sort(other_sorted+1,other_sorted+n+1,cmp_y);

    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,other_sorted[i].x)-help_x;

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

    int st=0;
    for(int i=1;i<=n;i++)
    {
        if((1<<st)<i)st++;

        SZ[i]=1<<st;

        bits[i]=st;

        //cout<<i<<" -> "<<SZ[i]<<" "<<bits[i]<<endl;
    }
    for(int i=1;i<MX;i++)
        if(nodes[i].size())
        {
            for(int j=0;j<nodes[i].size();j++)
            {
                prv[i].push_back(j-1);
                nxt[i].push_back(j+1);
            }
            build(i);
        }

    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)':
circle_selection.cpp:73:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   73 |     for(int i=0;i<nodes[where].size();i++)
      |                 ~^~~~~~~~~~~~~~~~~~~~
circle_selection.cpp: In function 'void match(int, int, int, int, int, circle)':
circle_selection.cpp:147:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  147 |         if(start==nodes[node].size())return;
      |            ~~~~~^~~~~~~~~~~~~~~~~~~~
circle_selection.cpp:162:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  162 |         while(start<nodes[node].size()&&nodes[node][start].first<=y2)
      |               ~~~~~^~~~~~~~~~~~~~~~~~~
circle_selection.cpp:184:28: 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]
  184 |             if(nxt[node][k]<nodes[node].size())
circle_selection.cpp: In function 'int main()':
circle_selection.cpp:260:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  260 |             for(int j=0;j<nodes[i].size();j++)
      |                         ~^~~~~~~~~~~~~~~~
circle_selection.cpp:272:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  272 |     for(int i=1;i<=n;i++)printf("%i ",outp[i]);printf("\n");
      |     ^~~
circle_selection.cpp:272:48: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
  272 |     for(int i=1;i<=n;i++)printf("%i ",outp[i]);printf("\n");
      |                                                ^~~~~~
circle_selection.cpp:222:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  222 |     scanf("%i",&n);
      |     ~~~~~^~~~~~~~~
circle_selection.cpp:225:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  225 |         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