Submission #941053

#	Time	Username	Problem	Language	Result	Execution time	Memory
941053		emad234	Stations (IOI20_stations)	C++17	Compilation error	0 ms	0 KiB

stations

#include<bits/stdc++.h>
#define ll long long
#define F first
#define S second
#define pii pair<int,int>
const int mxN = 1e5 + 1;
using namespace std;
vector<int> labelss,pre,post;
vector<vector<int>>gr;
int id;
void dfs(int u,int par){
	pre[u] = ++id;
	for(auto x : gr[u]){
		if(x == par) continue;
		dfs(x,u);
	}
	post[u] = ++id;
}
void labeling(int u,int par,int d){
	if(d % 2) labelss[u] = pre[u];
	else labelss[u] = post[u];
	cout<<labelss[u]<<' ';
	for(auto x : gr[u]){
		if(x == par) continue;
		labeling(x,u,d + 1);
	}
}
vector<int> label(int n, int k, std::vector<int> u, std::vector<int> v) {
	gr.resize(n + 1);
	labelss.resize(n);
	post.resize(n);
	pre.resize(n);
	for(int i = 0;i < n - 1;i++){
		gr[u[i]].push_back(v[i]);
		gr[v[i]].push_back(u[i]);
	}
	dfs(0,-1);
	labeling(0,-1,0);
	cout<<'\n';
	return labelss;
}

int find_next_station(int s, int t, std::vector<int> c) {
	bool pst = 1;
	int root = -1;
	for(auto x : c) {
		if(x > s) pst = 0;
	}
	for(auto x : c){
		if(pst) root == -1 ? root = x : root = min(root,x);
		else  root = max(x,root);
	}
	int id = root;
	if(pst){
		for(auto x :  c){
			if(x > t) break;
			else id = x;
		}
		if(s < t) id = root;
	}else{
		for(auto x : c){
			if(x > t){
				id = x;
				break;
			}
		}
	}
	return id;
}

static int max_label = 0;
static int r, n, k, q;
static std::vector<int> u, v, labels, answers;
static std::map<int, int> reverse_labels;
static std::vector<std::vector<int>> adjlist;
static int s, t, w;
static std::vector<int> c;

int main() {
	assert(scanf("%d", &r) == 1);
	for (int tc = 0; tc < r; tc++) {
		assert(scanf("%d%d", &n, &k) == 2);
		u.resize(n - 1);
		v.resize(n - 1);
		adjlist.clear();
		adjlist.resize(n);
		for (int i = 0; i < n - 1; i++) {
			assert(scanf("%d%d", &u[i], &v[i]) == 2);
			adjlist[u[i]].push_back(v[i]);
			adjlist[v[i]].push_back(u[i]);
		}
		labels = label(n, k, u, v);
		if ((int)labels.size() != n) {
			printf("Number of labels not equal to %d\n", n);
			exit(0);
		}
		reverse_labels.clear();
		for (int i = 0; i < n; i++) {
			if (labels[i] < 0 || labels[i] > k) {
				printf("Label not in range 0 to %d\n", k);
				exit(0);
			}
			if (reverse_labels.find(labels[i]) != reverse_labels.end()) {
				printf("Labels not unique\n");
				exit(0);
			}
			reverse_labels[labels[i]] = i;
			if (labels[i] > max_label) {
				max_label = labels[i];
			}
		}
		assert(scanf("%d", &q) == 1);
		for (int i = 0; i < q; i++) {
			assert(scanf("%d%d%d", &s, &t, &w) == 3);
			c.clear();
			for (int v : adjlist[s]) {
				c.push_back(labels[v]);
			}
			std::sort(c.begin(), c.end());
			int answer = find_next_station(labels[s], labels[t], c);
			if (!std::binary_search(c.begin(), c.end(), answer)) {
				printf("Label %d returned by find_next_station not found in c\n", answer);
				exit(0);
			}
			answers.push_back(reverse_labels[answer]);
		}
	}
	printf("%d\n", max_label);
	for (int index : answers) {
		printf("%d\n", index);
	}
	exit(0);
}

Compilation message (stderr)

/usr/bin/ld: /tmp/ccaAdZwS.o: in function `main':
stub.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/ccxbQMeQ.o:stations.cpp:(.text.startup+0x0): first defined here
collect2: error: ld returned 1 exit status