APIO 2018选圆圈

#include<cstdio>
#include<algorithm>
#include<cstring>
#include<iostream>
#include<queue>
#include<cmath>
#define sqr(x) (x) * (x)
#define M 300005
using namespace std;
const double inf = 1e20, eps = 1e-3, alpha = acos(-1) / 5, cosa = cos(alpha), sina = sin(alpha);
int n, root, ans[M], D,lc[M], rc[M], id[M];
double maxx[M][2], minn[M][2], deed[M][2], rn[M];
int read() {
    int nm = 0, f  =1;
    char c = getchar();
    for(; !isdigit(c); c = getchar()) if(c == '-') f = -1;
    for(; isdigit(c); c = getchar()) nm = nm * 10 + c  - '0';
    return nm * f;
}

struct C {
    double d[2], r;
    int id;
    bool operator < (C b) const {
        return d[D] < b.d[D];
    }
    double& operator [](int x) {
        return d[x];
    }

} note[M];

bool cmp(C a, C b) {
    return a.r == b.r ? a.id < b.id : a.r > b.r;
}

void updata(int x) {
    for(int i = 0; i <= 1; i++) {
        maxx[x][i] = minn[x][i] = deed[x][i];
        maxx[x][i] = max(maxx[x][i], max(maxx[lc[x]][i], maxx[rc[x]][i]));
        minn[x][i] = min(minn[x][i], min(minn[lc[x]][i], minn[rc[x]][i]));
    }
}

int build(int l, int r, int kx) {
    if(l > r) return 0;
    int mid = (l + r) >> 1;
    D = kx;
    nth_element(note + l, note + mid, note + r + 1);
    deed[mid][0] = note[mid][0], deed[mid][1] = note[mid][1];
    id[mid] = note[mid].id;
    rn[mid] = note[mid].r;
    lc[mid] = build(l, mid - 1, kx ^ 1), rc[mid] = build(mid + 1, r, kx ^ 1);
    updata(mid);
    return mid;
}
bool check(int x, C a)
{
    double xn = deed[x][0], yn = deed[x][1], xnn = a[0], ynn = a[1], r1 = rn[x], r2 = a.r;

    return sqr(xn - xnn) + sqr(yn - ynn) - sqr(r1 + r2)<= eps; 
}
bool cut(int x, C a) {
    double xn = a[0], yn = a[1], r = a.r + a.r; // 位被选中的圆形大小一定比当前小  依据这个来剪枝
    if(xn + r + eps < minn[x][0]) return true;
    if(yn + r + eps < minn[x][1]) return true;
    if(xn - r - eps > maxx[x][0]) return true;
    if(yn - r - eps > maxx[x][1]) return true;
    return false;
}
void modify(int x, C a) {
    if(x == 0) return;
    if(cut(x, a)) return;
    if(!ans[id[x]] && check(x, a)) ans[id[x]] = a.id;
    modify(lc[x], a) ,modify(rc[x], a);
}

int main() {
    maxx[0][1] = maxx[0][0] = -inf;
    minn[0][1] = minn[0][0] = inf;
    n = read();
    for(int i = 1; i <= n; i++) {
        double x = read(), y = read(), z = read();
        note[i] = (C) {
            x * cosa - y * sina, x * sina + y * cosa, z, i
        };
    }
    root = build(1, n, 0);
    sort(note + 1, note + n + 1, cmp);
    for(int i = 1; i <= n; i++)
        if(!ans[note[i].id]) modify(root, note[i]);
    for(int i = 1; i <= n; i++) printf("%d ", ans[i]);
    return 0;
}