Submission #963468

#	Time	Username	Problem	Language	Result	Execution time	Memory
963468		vjudge1	City Mapping (NOI18_citymapping)	C++17	32 / 100	202 ms	856 KiB

citymapping

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define ent "\n"

const int maxn = 4e3 + 100;
const ll INF = (ll)1e18 + 100;
const int inf = 1e9 + 100;
const int MOD = 1e9 + 7;
const int maxl = 30;
const int P = 31;

long long get_distance(int X, int Y);

int n;
vector<int> g[maxn];
ll d[maxn][maxn];
vector<pii> ans;
int sz[maxn];
int mx[maxn];

void get(int v, int del){
	sz[v] = 1; mx[v] = 0;
	for(int to: g[v]){
		if(to == del) continue;
		get(to, del);
		if(sz[to] > sz[mx[v]]) mx[v] = to;
	}
}

void find_roads(int N, int Q, int A[], int B[], int W[]){
	n = N;
	vector<int> v;
	for(int i = 2; i <= n; i++){
		v.push_back(i);
		d[1][i] = get_distance(1, i);
	}
	sort(v.begin(), v.end(), [](int i, int j){
		return d[1][i] < d[1][j];
	});
	int edg = 0;
	for(int i: v){
		int r = 1, del = 0;
		while(true){
			get(r, del);
			vector<int> s;
			s.push_back(r);
			while(mx[s.back()]){
				s.push_back(mx[s.back()]);
			}
			if(s.size() == 1) break;
			ll x = d[1][s.back()] + d[1][i] - get_distance(s.back(), i);
			x /= 2; int j = 0;
			while(d[1][s[j]] != x) j++;
			r = s[j]; if(j + 1 < s.size()) del = s[j+1];
		}
		A[edg] = r; B[edg] = i;
		W[edg] = d[1][i] - d[1][r];
		edg++; g[r].push_back(i);
	}
}

Compilation message (stderr)

citymapping.cpp: In function 'void find_roads(int, int, int*, int*, int*)':
citymapping.cpp:57:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |    r = s[j]; if(j + 1 < s.size()) del = s[j+1];
      |                 ~~~~~~^~~~~~~~~~

• Subtask 1: 0 / 9
• Subtask 2: 0 / 16
• Subtask 3: 13 / 13
• Subtask 4: 19 / 19
• Subtask 5: 0 / 43