Submission #31020

#	Time	Username	Problem	Language	Result	Execution time	Memory
31020		kajebiii	Towns (IOI15_towns)	C++14	100 / 100	29 ms	2076 KiB

towns

#include "towns.h"
#include <bits/stdc++.h>

using namespace std;

#define SZ(v) ((int)(v).size())
#define ALL(v) (v).begin(),(v).end()
#define one first
#define two second
typedef long long ll;
typedef unsigned long long ull;
typedef pair<double, double> pd;
typedef pair<int, int> pi;
typedef pair<ll, int> pli;
typedef pair<ll, ll> pll; typedef pair<ll, pi> plp;
typedef tuple<int, int, int> ti; typedef tuple<ll, int, int> tli;
const int INF = 0x3f2f1f0f;
const ll LINF = 1ll * INF * INF * 2;

map<pi, int> Mp;
int getD(int i, int j) {
    if(Mp.count(pi(i, j)) == 0) Mp[pi(i, j)] = Mp[pi(j, i)] = getDistance(i, j);
    return Mp[pi(i, j)];
}

int N, Sub;
int max0D, f, maxfD, s;
bool isDiff(int a, int b, int dis) {
//    return a != b;
    return (getD(f, a) + getD(f, b) - 2 * dis) == getD(a, b);
}
bool haveMajor(int dis, vector<int> candi) {
    if(SZ(candi) == 0) return false;
    vector<int> minor;
    vector<pi> rep;
    int nowX = -1, nowL = 0, maxL = 0;
    for(int x : candi) {
        if(nowX == -1) {
            nowX = x; nowL = maxL = 1;
        }else{
            if(!isDiff(nowX, x, dis)) nowL++, maxL++;
            else{
                nowL--;
                minor.push_back(x);
                if(nowL == 0) {
                    rep.push_back(pi(nowX, maxL));
                    nowX = -1;
                }
            }
        }
    }
    if(nowX != -1) rep.push_back(pi(nowX, maxL));
//    for(pi e : rep) printf("[%d %d] ", e.one, e.two); puts(""); for(int x : minor) printf("%d ", x); puts("");

    int mj = rep.back().one, cnt = 0;
    for(pi e : rep) if(!isDiff(mj, e.one, dis)) cnt += e.two;
    for(int x : minor) if(!isDiff(mj, x, dis)) cnt++;
//    return cnt > SZ(candi) / 2;
    return cnt > N/2;
}
int hubDistance(int n, int sub) {
    Mp.clear();
    N = n; Sub = sub;

    max0D = -1, f = -1;
    for(int i=0; i<N; i++) {
        if(i == 0) continue;
        int d = getD(0, i);
        if(max0D < d) max0D = d, f = i;
    }
    maxfD = -1, s = -1;
    for(int i=0; i<N; i++) {
        if(i == f) continue;
        int d = getD(f, i);
        if(maxfD < d) maxfD = d, s = i;
    }

    int R = INF;
    int from0 = (getD(0, f) + getD(0, s) - getD(s, f)) / 2;
    vector<pi> list;
    for(int i=0; i<N; i++) {
        int dis = (getD(0, i) + getD(0, f) - getD(i, f)) / 2;
        int r = -1;
        if(dis >= from0) {
            r = max0D - dis;
            R = min(R, max(r, maxfD - r));
        }else{
            r = max0D - from0;
        }
        list.push_back(pi(r, i));
    }
    sort(ALL(list));

    int lim = N/2;
//    printf("f %d | s %d\n", f, s); for(pi &e : list) printf("[%d %d] ", e.one, e.two);
    for(int i=0, j=0; i<N; i=j) {
        vector<int> candi;
        int r = list[i].one;
        while(j<N && list[i].one == list[j].one) candi.push_back(list[j++].two);
        if(R == max(r, maxfD - r)) {
            if(i <= lim && N-j <= lim && j-i <= lim) return R;
            if(i <= lim && N-j <= lim && j-i >  lim)
                if(!haveMajor(r, candi)) return R;
        }
    }

    return -R;
}

• Subtask 1: 13 / 13
• Subtask 2: 12 / 12
• Subtask 3: 13 / 13
• Subtask 4: 10 / 10
• Subtask 5: 13 / 13
• Subtask 6: 39 / 39