Submission #552187

#	Time	Username	Problem	Language	Result	Execution time	Memory
552187		hoanghq2004	Stations (IOI20_stations)	C++14	100 / 100	848 ms	944 KiB

stations

#include <bits/stdc++.h>
#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include "stations.h"

using namespace __gnu_pbds;
using namespace std;

template <typename T>
using ordered_set = tree <T, null_type, less <T>, rb_tree_tag, tree_order_statistics_node_update>;

mt19937 gen(std :: chrono :: system_clock :: now().time_since_epoch().count());

const int N = 2e3 + 10;

int in[N], out[N], ti;
vector <int> g[N];
int depth[N];

void dfs(int u, int p, int d) {
    in[u] = ++ti;
    depth[u] = d;
    for (auto v: g[u]) {
        if (v == p) continue;
        dfs(v, u, d ^ 1);
    }
    out[u] = ++ti;
}

int a[N];

vector <int> label(int n, int k, vector <int> U, vector <int> V) {
    for (int i = 0; i < n - 1; ++i) {
        g[U[i]].push_back(V[i]);
        g[V[i]].push_back(U[i]);
    }
    dfs(0, -1, 0);
    vector <int> ans, dta;
    for (int i = 0; i < n; ++i)
        a[i] = (!depth[i] ? out[i] : in[i]);
//    for (int i = 0; i < n; ++i)
//        cout << in[i] << ' ' << out[i] << '\n';
    for (int i = 0; i < n; ++i) dta.push_back(a[i]);
    sort(dta.begin(), dta.end());
    for (int i = 0; i < n; ++i) ans.push_back(lower_bound(dta.begin(), dta.end(), a[i]) - dta.begin());
    ti = 0;
    for (int i = 0; i < n; ++i) in[i] = out[i] = depth[i] = 0, g[i].clear();
    return ans;
}

int find_next_station(int s, int t, vector <int> g) {
    if (g[0] > s) { // in
        if (t < s) return g.back();
        for (int i = 0; i < g.size(); ++i)
            if (t <= g[i]) return g[i];
        return g.back();
    } else { // out
        if (t > s) return g.front();
        for (int i = g.size() - 1; i >= 0; --i)
            if (t >= g[i]) return g[i];
        return g.front();
    }
}
//
//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)

stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:56:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |         for (int i = 0; i < g.size(); ++i)
      |                         ~~^~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 8 / 8
• Subtask 3: 16 / 16
• Subtask 4: 10 / 10
• Subtask 5: 61 / 61