Submission #1040011

#	Time	Username	Problem	Language	Result	Execution time	Memory
1040011		c2zi6	Towns (IOI15_towns)	C++14	35 / 100	8 ms	484 KiB

towns

#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define all(a) (a).begin(), (a).end()
#define replr(i, a, b) for (int i = int(a); i <= int(b); ++i)
#define reprl(i, a, b) for (int i = int(a); i >= int(b); --i)
#define rep(i, n) for (int i = 0; i < int(n); ++i)
#define mkp(a, b) make_pair(a, b)
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> PII;
typedef vector<int> VI;
typedef vector<PII> VPI;
typedef vector<VI> VVI;
typedef vector<VVI> VVVI;
typedef vector<VPI> VVPI;
typedef pair<ll, ll> PLL;
typedef vector<ll> VL;
typedef vector<PLL> VPL;
typedef vector<VL> VVL;
typedef vector<VVL> VVVL;
typedef vector<VPL> VVPL;
template<class T> T setmax(T& a, T b) {if (a < b) return a = b; return a;}
template<class T> T setmin(T& a, T b) {if (a < b) return a; return a = b;}
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template<typename T>
using indset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#include "towns.h"

int maxind(VL& a) {
    int ret;
    ll mx = -1e18;
    rep(i, a.size()) if (a[i] > mx) {
        mx = a[i];
        ret = i;
    }
    return ret;
}

int hubDistance(int N, int SUBTASK) {
    int q = 0;

    int n = N;
    VL dist0, distd1, distd2, distl, distr, disth;
    dist0 = distd1 = distd2 = distl = distr = disth = VL(n);
    rep(u, n) dist0[u] = getDistance(0, u), q++;
    int d1 = maxind(dist0);
    rep(u, n) distd1[u] = getDistance(d1, u), q++;
    int d2 = maxind(distd1);
    rep(u, n) distd2[u] = getDistance(d2, u), q++;

    ll R = 1e18;
    rep(u, n) {
        disth[u] = (distd1[u] + distd2[u] - distd1[d2])/2;
        distl[u] = distd1[u]-disth[u];
        distr[u] = distd2[u]-disth[u];
        setmin(R, max(distl[u], distr[u]));
    }
    VI anc(n);
    /* 0, on the left
     * 1, first hub
     * 2, second hub
     * 3, on the right
     */
    rep(u, n) {
        if (max(distl[u], distr[u]) == R) {
            if (distl[u] <= distr[u]) anc[u] = 1;
            else anc[u] = 2;
        } else {
            if (distl[u] <= distr[u]) anc[u] = 0;
            else anc[u] = 3;
        }
    }

    int cnt[4]{};
    for (int x : anc) cnt[x]++;
    if (SUBTASK == 4) {
        if (cnt[0] <= N/2 && cnt[1] <= N/2 && cnt[2] + cnt[3] <= N/2) return +R;
        if (cnt[0] + cnt[1] <= N/2 && cnt[2] <= N/2 && cnt[3] <= N/2) return +R;
        return -R;
    } else if (SUBTASK == 3) {
        return -R;
        auto check = [&](int u, int v) {
            return disth[u] + disth[v] != getDistance(u, v), q++;
        };
        VI a;
        replr(HUBIND, 1, 2) {
            a = VI();
            rep(i, n) if (anc[i] == HUBIND) a.pb(i);
            if (a.size() == 0) continue;

            VI subtrees;
            subtrees.pb(cnt[0]);
            subtrees.pb(cnt[3]);

            VI group(n);
            int g = 1;
            for (int i : a) if (group[i] == 0) {
                group[i] = g;
                subtrees.pb(1);
                for (int j : a) if (group[j] == 0) {
                    if (check(i, j)) {
                        group[j] = g;
                        subtrees.back()++;
                    }
                }
                g++;
            }

            bool good = true;
            for (int x : subtrees) {
                if (x > N/2) good = false;
            }
            if (good) {
                assert(q <= N * (N-1) /2);
                return -R;
            }
        }
        assert(q <= N * (N-1) /2);
        return +R;
    }
	return R;
}

Compilation message (stderr)

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:82:78: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
   82 |         if (cnt[0] <= N/2 && cnt[1] <= N/2 && cnt[2] + cnt[3] <= N/2) return +R;
      |                                                                              ^~
towns.cpp:83:78: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
   83 |         if (cnt[0] + cnt[1] <= N/2 && cnt[2] <= N/2 && cnt[3] <= N/2) return +R;
      |                                                                              ^~
towns.cpp:84:16: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
   84 |         return -R;
      |                ^~
towns.cpp:86:16: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
   86 |         return -R;
      |                ^~
towns.cpp: In lambda function:
towns.cpp:88:40: warning: value computed is not used [-Wunused-value]
   88 |             return disth[u] + disth[v] != getDistance(u, v), q++;
towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:120:24: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
  120 |                 return -R;
      |                        ^~
towns.cpp:124:16: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
  124 |         return +R;
      |                ^~
towns.cpp:126:9: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
  126 |  return R;
      |         ^
towns.cpp: In function 'int maxind(VL&)':
towns.cpp:41:12: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
   41 |     return ret;
      |            ^~~
towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:54:38: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
   54 |     rep(u, n) distd2[u] = getDistance(d2, u), q++;
      |                           ~~~~~~~~~~~^~~~~~~
towns.cpp:52:38: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
   52 |     rep(u, n) distd1[u] = getDistance(d1, u), q++;
      |                           ~~~~~~~~~~~^~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 12 / 12
• Subtask 3: 0 / 13
• Subtask 4: 10 / 10
• Subtask 5: 0 / 13
• Subtask 6: 0 / 39