Submission #48879

#	Time	Username	Problem	Language	Result	Execution time	Memory
48879		top34051	Circle selection (APIO18_circle_selection)	C++17	0 / 100	3084 ms	487460 KiB

circle_selection

#include<bits/stdc++.h>
using namespace std;

#define ll long long
const int maxn = 3e5 + 5;

struct node {
    ll x,y,r;
};

int n;
node p[maxn];
ll R;
ll xx[maxn], yy[maxn];
unordered_map<ll,unordered_map<ll,set<int>>> a;
int ok[maxn], res[maxn];

vector<int> del;

double dist(node a, node b) {
    return sqrt((double)(a.x-b.x)*(a.x-b.x) + (double)(a.y-b.y)*(a.y-b.y));
}

int main() {
    scanf("%d",&n);
    for(int i=1;i<=n;i++) scanf("%lld%lld%lld",&p[i].x,&p[i].y,&p[i].r);

    ll R = p[1].r;
    for(int i=1;i<=n;i++) {
        xx[i] = p[i].x/R;
        yy[i] = p[i].y/R;
        a[xx[i]][yy[i]].insert(i);
//        printf("%lld %lld : %d\n",p[i].x/R,p[i].y/R,i);
    }

    for(int x=1;x<=n;x++) {
        if(ok[x]) continue;
//        printf("x = %d\n",x);
        for(ll i=xx[x]-2;i<=xx[x]+2;i++) {
            for(ll j=yy[x]-2;j<=yy[x]+2;j++) {
                del.clear();
                for(auto y : a[i][j]) {
//                    printf("\ty = %d\n",y);
                    if(ok[y]) continue;
                    if(dist(p[x],p[y])<=(double)R*2) {
                        ok[y] = 1;
                        res[y] = x;
                        del.push_back(y);
                    }
                }
                for(auto y : del) a[i][j].erase(y);
            }
        }
    }

    for(int x=1;x<=n;x++) printf("%d ",res[x]);
}

Compilation message (stderr)

circle_selection.cpp: In function 'int main()':
circle_selection.cpp:25:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ~~~~~^~~~~~~~~
circle_selection.cpp:26:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for(int i=1;i<=n;i++) scanf("%lld%lld%lld",&p[i].x,&p[i].y,&p[i].r);
                           ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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