제출 #410995

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
410995		ja_kingy	도시들 (IOI15_towns)	C++14	35 / 100	19 ms	460 KiB

towns

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

int hubDistance(int n, int sub) {
	vector<int> d0(n), d1(n);
	int mx = 0, R = 1e9;
	for (int i = 1; i < n; ++i) {
		d0[i] = getDistance(0, i);
		if (d0[i] > d0[mx]) mx = i;
	}
	d1[0] = d0[mx];
	int d = d0[mx];
	map<int, vector<int>> groups;
	for (int i = 1; i < n; ++i) if (i != mx) {
		d1[i] = getDistance(mx, i);
		groups[(d1[i] - d0[i] + d0[mx]) / 2].push_back(i);
		d = max(d, d1[i]);
	}
	int hub = 0, lft = 1, rht = n-1;
	for (auto g: groups) {
		R = min(R, max(g.first, d-g.first));
	}
	for (auto g: groups) {
		rht -= g.second.size();
		if (max(g.first, d-g.first) == R) {
			if (lft <= n/2 && rht <= n/2) {
				//for (int i: g.second) cerr << i << ' ';
				//cerr << endl;
				vector<int> head(n), sz(n,1);
				int mst = g.second[0], cnt=1, qcnt=0;
				auto same_st = [&](int a, int b) {qcnt++;return getDistance(a, b) != d1[a]+d1[b] - 2*g.first;};
				for (int i = 1; i < g.second.size(); ++i) {
					if (same_st(mst, g.second[i])) {
						// cerr << "same " << mst << ' ' << g.second[i] << endl;
						cnt++;
						head[g.second[i]] = mst;
						sz[mst]++;
					} else {
						// cerr << "not same " << mst << ' ' << g.second[i] << endl;
						head[g.second[i]] = g.second[i];
						if (cnt == 0) {
							mst = g.second[i];
							cnt = 1;
						} else cnt--;
					}
				}
				//cerr << mst << endl;
				for (int i = g.second.size(); i--;) if (g.second[i] != mst) {
					// cerr << g.second[i] << ' ' << head[g.second[i]] << endl;
					if (g.second[i] == head[g.second[i]]) {
						if (same_st(mst, g.second[i])) {
							// cerr << "same " << mst << ' ' << g.second[i] << endl;
							sz[mst] += sz[g.second[i]];
						}
						//if (qcnt > n) return -R;
					}
				}
				if (sz[mst] >= n/2) return -R;
				return R;
			}
		}
		lft += g.second.size();
	}
	return -R;
}

컴파일 시 표준 에러 (stderr) 메시지

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:25:24: warning: conversion from 'std::vector<int>::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   25 |   rht -= g.second.size();
      |                        ^
towns.cpp:33:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   33 |     for (int i = 1; i < g.second.size(); ++i) {
      |                     ~~^~~~~~~~~~~~~~~~~
towns.cpp:49:31: warning: conversion from 'std::vector<int>::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   49 |     for (int i = g.second.size(); i--;) if (g.second[i] != mst) {
      |                  ~~~~~~~~~~~~~^~
towns.cpp:63:24: warning: conversion from 'std::vector<int>::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   63 |   lft += g.second.size();
      |                        ^
towns.cpp:20:6: warning: unused variable 'hub' [-Wunused-variable]
   20 |  int hub = 0, lft = 1, rht = n-1;
      |      ^~~
towns.cpp:5:28: warning: unused parameter 'sub' [-Wunused-parameter]
    5 | int hubDistance(int n, int sub) {
      |                        ~~~~^~~

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