제출 #362024

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
362024		valerikk	기지국 (IOI20_stations)	C++17	52.32 / 100	1085 ms	1372 KiB

stations

#include <bits/stdc++.h>

using namespace std; 

const int N = 1000;

vector<int> g[N];
int T = 0;
vector<int> l;

int dfs(int v, int p = -1) {
    l[v] = T++;
    int mx = l[v];
    for (int u : g[v]) {
        if (u != p) mx = max(mx, dfs(u, v));
    }
    l[v] *= N;
    l[v] += mx;
    return mx;
}

vector<int> label(int n, int k, vector<int> u, vector<int> v) {
    for (int i = 0; i < n; i++) g[i].clear();
    for (int i = 0; i < n - 1; i++) {
        g[u[i]].push_back(v[i]);
        g[v[i]].push_back(u[i]);
    }
    l.resize(n);
    T = 0;
    dfs(0);
    //for (int &i : l) assert(i >= 0 && i <= k);
    return l;
}

int find_next_station(int s, int t, vector<int> c) {
    int p;
    for (int v : c) {
        if (v / N <= s / N && s / N <= v % N) p = v; else {
            if (v / N <= t / N && t / N <= v % N) return v;
        } 
    }
    return p;
}

#ifdef LOCAL
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);
}
#endif

컴파일 시 표준 에러 (stderr) 메시지

stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:36:9: warning: 'p' may be used uninitialized in this function [-Wmaybe-uninitialized]
   36 |     int p;
      |         ^

• Subtask 1: 0 / 5
• Subtask 2: 0 / 8
• Subtask 3: 16 / 16
• Subtask 4: 10 / 10
• Subtask 5: 26.3205 / 61