oj.uz

Submission #1018916

# Submission time Handle Problem Language Result Execution time Memory
1018916 2024-07-10T10:50:24 Z AmirAli_H1 Towns (IOI15_towns) C++17
48 / 100
 12 ms 1116 KB 
// In the name of Allah

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

typedef		long long int			ll;
typedef		long double				ld;
typedef		pair<int, int>			pii;
typedef		pair<ll, ll>			pll;
typedef		complex<ld>				cld;

#define		all(x)					(x).begin(),(x).end()
#define		len(x)					((ll) (x).size())
#define		F						first
#define		S						second
#define		pb						push_back
#define		sep						' '
#define		endl					'\n'
#define		Mp						make_pair
#define		kill(x)					cout << x << '\n', exit(0)
#define		set_dec(x)				cout << fixed << setprecision(x);
#define		file_io(x,y)			freopen(x, "r", stdin); freopen(y, "w", stdout);
mt19937 rng(23232323);

int n, vx;
const int maxn = 110 + 4;
ll dis[maxn][maxn];
ll D1[maxn], D2[maxn];
ll ans, R, dx; bool f1, f2, ok;
int p[maxn], sz[maxn], mark[maxn];
vector<int> ls;

int get(int a) {
	return (p[a] == a) ? a : p[a] = get(p[a]);
}

void merge(int a, int b) {
	a = get(a); b = get(b);
	if (a == b) return ;
	if (sz[a] > sz[b]) swap(a, b);
	p[a] = b; sz[b] += sz[a]; sz[a] = 0;
}

ll get_dis(int u, int v) {
	if (dis[u][v] == -1) {
		dis[u][v] = dis[v][u] = getDistance(u, v);
	}
	return dis[u][v];
}

void calx() {
	f1 = 0, f2 = 0; ok = 0;
	for (int i = 0; i < n; i++) {
		ll x = (D1[i] + D2[i] - dx) / 2;
		if (D1[i] - x == R) f1 = 1;
		if (D2[i] - x == R) f2 = 1;
	}
	
	int t1 = 0, t2 = 0;
	for (int i = 0; i < n; i++) {
		ll x = (D1[i] + D2[i] - dx) / 2;
		ll d = D1[i] - x;
		if (d < R) t1++;
		else if (d > R) t2++;
	}
	if (max(t1, t2) * 2 <= n) ok = 1;
	
	t1 = 0, t2 = 0;
	for (int i = 0; i < n; i++) {
		ll x = (D1[i] + D2[i] - dx) / 2;
		ll d = D2[i] - x;
		if (d < R) t1++;
		else if (d > R) t2++;
	}
	if (max(t1, t2) * 2 <= n) ok = 1;
}

void solve3() {
	for (int i = 0; i < n; i++) {
		for (int j = i + 1; j < n; j++) {
			ll x1 = (D1[i] + D2[i] - dx) / 2;
			ll x2 = (D1[j] + D2[j] - dx) / 2;
			ll d = (x1 + x2 - get_dis(i, j)) / 2;
			if (d > 0) merge(i, j);
		}
	}
	
	int mx = *max_element(sz, sz + n);
	if (2 * mx > n) ans = -ans;
	return ;
}

void solve4() {
	if (f1) {
		int t = 0;
		for (int i = 0; i < n; i++) {
			ll x = (D1[i] + D2[i] - dx) / 2;
			ll d = D1[i] - x;
			if (d == R) t++;
		}
		if (2 * t <= n) return ;
	}
	if (f2) {
		int t = 0;
		for (int i = 0; i < n; i++) {
			ll x = (D1[i] + D2[i] - dx) / 2;
			ll d = D2[i] - x;
			if (d == R) t++;
		}
		if (2 * t <= n) return ;
	}
	
	ans = -ans;
	return ;
}

void solvex() {
	fill(mark, mark + n, 0);
	int i = -1;
	for (int T = 0; T < 3; T++) {
		ls.clear();
		for (int j = 0; j < n; j++) {
			if (!mark[j]) ls.pb(j);
		}
		
		if (i == -1) i = vx;
		else i = ls[rng() % len(ls)];
		
		mark[i] = 1;
		for (int j = 0; j < n; j++) {
			if (i == j) continue;
			ll x1 = (D1[i] + D2[i] - dx) / 2;
			ll x2 = (D1[j] + D2[j] - dx) / 2;
			ll d = (x1 + x2 - get_dis(i, j)) / 2;
			if (d > 0) {
				merge(i, j); mark[j] = 1;
			}
		}
		if (sz[get(i)] * 2 > n) {
			ans = -ans;
			return ;
		}
	}
	return ;
}

int hubDistance(int N, int sub) {
	n = N;
	
	iota(p, p + n, 0); fill(sz, sz + n, 1);
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (i == j) dis[i][j] = 0;
			else dis[i][j] = -1;
		}
	}
	
	vx = rng() % n;
	ll mx = 0; int u1 = vx;
	for (int i = 0; i < n; i++) {
		if (i == vx) continue;
		ll d = get_dis(vx, i);
		if (d >= mx) {
			mx = d; u1 = i;
		}
	}
	
	mx = 0; int u2 = u1;
	for (int i = 0; i < n; i++) {
		if (i == u1) {
			D1[i] = 0;
			continue;
		}
		D1[i] = get_dis(u1, i);
		if (D1[i] >= mx) {
			mx = D1[i]; u2 = i;
		}
	}
	
	for (int i = 0; i < n; i++) {
		if (i == u2) {
			D2[i] = 0;
			continue;
		}
		D2[i] = get_dis(u2, i);
	}
	
	dx = D1[u2]; R = dx;
	for (int i = 0; i < n; i++) {
		ll x = (D1[i] + D2[i] - dx) / 2;
		R = min(R, max(D1[i] - x, D2[i] - x));
	}
	ans = R;
	
	calx();
	if (!ok) return -ans;
	
	if (sub == 3) solve3();
	else if (sub == 4) solve4();
	else if (sub >= 5) solvex();
	
	return ans;
}

Compilation message

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:159:13: warning: conversion from 'std::mersenne_twister_engine<long unsigned int, 32, 624, 397, 31, 2567483615, 11, 4294967295, 7, 2636928640, 15, 4022730752, 18, 1812433253>::result_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
  159 |  vx = rng() % n;
      |       ~~~~~~^~~
towns.cpp:197:18: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
  197 |  if (!ok) return -ans;
      |                  ^~~~
towns.cpp:203:9: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
  203 |  return ans;
      |         ^~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 348 KB Output is correct
2 Correct 7 ms 580 KB Output is correct
3 Correct 0 ms 344 KB Output is correct
4 Correct 9 ms 584 KB Output is correct
5 Correct 9 ms 580 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 348 KB Output is correct
2 Correct 7 ms 348 KB Output is correct
3 Correct 9 ms 348 KB Output is correct
4 Correct 10 ms 584 KB Output is correct

Subtask #3
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 580 KB Output is correct
2 Correct 10 ms 1116 KB Output is correct
3 Correct 0 ms 444 KB Output is correct
4 Correct 10 ms 1112 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 348 KB Output is correct

Subtask #5
0 / 13.0

# Verdict Execution time Memory Grader output
1 Incorrect 7 ms 348 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #6
0 / 39.0

# Verdict Execution time Memory Grader output
1 Incorrect 2 ms 600 KB Output isn't correct
2 Halted 0 ms 0 KB -