Submission #538956

#	Time	Username	Problem	Language	Result	Execution time	Memory
538956		ac2hu	City Mapping (NOI18_citymapping)	C++14	9 / 100	187 ms	63100 KiB

citymapping

#include<bits/stdc++.h>
#include "citymapping.h"
using namespace std;
const int N = 1e3 + 1;
long long dist[N][N];
int n;
int par[N];
long long gd(int x,int y){
	if(dist[x][y] != -1) return dist[x][y];
	long long temp = get_distance(x + 1, y + 1);
	dist[x][y] = temp;
	dist[y][x] = temp;
	return temp;
}
bool inpath(int a,int b, int c){// check if c lies on a - b
	return gd(a, c) + gd(c, b) == gd(a, b);
}
void dfs(int r,int p, set<int> temp){
	par[r] = p;
	if(temp.size() == 0)
		return;
	vector<pair<long long,int>> tt;
	for(int j : temp){
		tt.push_back({gd(r, j), j});
	}
	sort(tt.begin(),tt.end());
	while(tt.size() > 3)
		tt.pop_back();
	while(tt.size() > 1 && inpath(r, tt[1].second, tt[0].second)){
		tt.erase(tt.begin() + 1);
	}
	for(int al = 0;al<2;al++){
		if(tt.size() > 2 && inpath(r, tt[2].second, tt[al].second)){
			tt.erase(tt.begin() + 2);
		}
	}
	for(int al = 0;al<tt.size();al++){
		temp.erase(temp.find(tt[al].second));
	}
	// Only children are in tt
	vector<set<int>> hold(tt.size());
	for(auto e : temp){
		for(int i = 0;i<tt.size();i++){
			if(inpath(r, e , tt[i].second)){
				hold[i].insert(e);
				break;
			}
		}
	}
	for(int i = 0;i<tt.size();i++){
		dfs(tt[i].second, r , hold[i]);
	}
}
void find_roads(int N, int Q, int A[], int B[], int W[]) {
	n = N;
	for(int i = 0;i<N;i++){
		for(int j = 0;j<N;j++){
			dist[i][j] = -1;
		}
	}
	int r = 0;
	set<int> temp;
	for(int i = 0;i<n;i++){
		if(r == i)continue;
		temp.insert(i);
	}
	// vector<array<int,3>> edges;
	dfs(r, -1, temp);
	vector<array<int,3>> edges;
	int p1 = 0;
	for(int i = 0;i<n;i++){
		if(i != r){
			edges.push_back({i + 1, par[i] + 1, (int)gd(i,par[i])});
		}
	}
	for(int i = 0;i<n-1;i++){
		A[i] = edges[i][0], B[i] = edges[i][1], W[i] = edges[i][2];
	}
	return;
}

Compilation message (stderr)

citymapping.cpp: In function 'void dfs(int, int, std::set<int>)':
citymapping.cpp:37:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   37 |  for(int al = 0;al<tt.size();al++){
      |                 ~~^~~~~~~~~~
citymapping.cpp:43:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |   for(int i = 0;i<tt.size();i++){
      |                 ~^~~~~~~~~~
citymapping.cpp:50:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   50 |  for(int i = 0;i<tt.size();i++){
      |                ~^~~~~~~~~~
citymapping.cpp: In function 'void find_roads(int, int, int*, int*, int*)':
citymapping.cpp:70:6: warning: unused variable 'p1' [-Wunused-variable]
   70 |  int p1 = 0;
      |      ^~

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