oj.uz

Submission #60686

# Submission time Handle Problem Language Result Execution time Memory
60686 2018-07-24T14:12:46 Z reality Towns (IOI15_towns) C++17
49 / 100
 39 ms 1132 KB 
#include "towns.h"
#include "bits/stdc++.h"
using namespace std;
#define fi first
#define se second
#define ll long long
#define dbg(v) cerr<<#v<<" = "<<v<<'\n'
#define vi vector<int>
#define vl vector <ll>
#define pii pair<int,int>
#define mp make_pair
#define db long double
#define pb push_back
#define all(s) s.begin(),s.end()
template < class T > T smin(T &a,T b) {if (a > b) a = b;return a;}
template < class T > T smax(T &a,T b) {if (a < b) a = b;return a;}
 
const int N = 256;
 
int D[N][N];
 
int get(int x,int y) {
	if (D[x][y] != -1)
		return D[x][y];
	return D[x][y] = D[y][x] = getDistance(x,y);
}
 
int dist[666];

int ans = 2e9;

int x = 0;

int n;

int go(int dt) {
	vi was(n,1);
	int a = 0,b = 0;
	for (int i = 0;i < n;++i) {
		int curr = get(x,i) - dist[i];
		if (curr < dt)
			++a,was[i] = 0;
		if (curr > dt)
			++b,was[i] = 0;
	}
	if (max({a,b}) > (n / 2))
		return -ans;
	auto ok = [&](int A,int B) {
		return get(A,B) != dist[A] + dist[B];
	};
	int cnt = 0;
	int cur = -1;
	for (int i = 0;cnt <= (n / 2) && i < n;++i)
		if (was[i]) {
			if (!cnt) {
				cur = i;
				cnt = 1;
			} else 
			if (ok(cur,i)) {
				++cnt;
			} else {
				--cnt;
			}
		}
	if (cnt > (n / 2))
		return -ans;
	int nr = 0;
	for (int i = 0;i < n;++i)
		if (was[i])
			nr += ok(i,cur);
	if (nr <= (n / 2))
		return ans;
	else
		return -ans;
}

int hubDistance(int N, int sub) {
	n = N;
	srand(time(0));
	const int root = 0;
	memset(D,-1,sizeof(D));
	for (int i = 0;i < n;++i)
		D[i][i] = 0;
	x = root;
	ans = 2e9;
	for (int i = 0;i < n;++i)
		if (get(root,i) > get(root,x))
			x = i;
	int y = x;
	for (int i = 0;i < n;++i)
		if (get(x,i) > get(x,y))
			y = i;
	const int Diam = get(x,y);
	int t = -1;
	for (int i = 0;i < n;++i) {
		dist[i] = (get(root,i) + get(x,i) - get(root,x)) / 2;
		int dx = get(x,i) - dist[i];
		smin(ans,max(Diam - dx,dx));
		if (max(Diam - dx,dx) == ans)
			t = dx;
	}
	return max(go(t),go(Diam - t));
}

Compilation message

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:77:31: warning: declaration of 'N' shadows a global declaration [-Wshadow]
 int hubDistance(int N, int sub) {
                               ^
towns.cpp:18:11: note: shadowed declaration is here
 const int N = 256;
           ^
towns.cpp:79:12: warning: conversion to 'unsigned int' from 'time_t {aka long int}' may alter its value [-Wconversion]
  srand(time(0));
        ~~~~^~~
towns.cpp:77:28: warning: unused parameter 'sub' [-Wunused-parameter]
 int hubDistance(int N, int sub) {
                            ^~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 632 KB Output is correct
2 Correct 20 ms 848 KB Output is correct
3 Correct 4 ms 848 KB Output is correct
4 Correct 26 ms 848 KB Output is correct
5 Correct 35 ms 848 KB Output is correct

Subtask #2
0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 38 ms 852 KB Output is correct
2 Correct 19 ms 852 KB Output is correct
3 Incorrect 6 ms 852 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #3
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 852 KB Output is correct
2 Correct 35 ms 852 KB Output is correct
3 Correct 4 ms 852 KB Output is correct
4 Correct 39 ms 956 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 29 ms 956 KB Output is correct

Subtask #5
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 956 KB Output is correct
2 Correct 31 ms 956 KB Output is correct
3 Correct 38 ms 956 KB Output is correct

Subtask #6
0 / 39.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 956 KB Output is correct
2 Incorrect 9 ms 1132 KB Output isn't correct
3 Halted 0 ms 0 KB -