oj.uz

답안 #144948

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
144948 2019-08-18T09:07:57 Z Vlatko Network (BOI15_net) C++14
0 / 100
 13 ms 12152 KB 
#include <bits/stdc++.h>
using namespace std;

void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif

typedef long long ll;
typedef pair<int, int> pii;


const int maxn = 500050;

int n;
vector<int> adj[maxn];

int depth[maxn];
vector<int> leaves;

vector<pii> edges;

void dfs(int u, int p) {
    if (adj[u].size() == 1 && (adj[u][0] == p || p == -1)) {
        leaves.push_back(u);
    }
    for (int v : adj[u]) {
        if (v != p) {
            depth[v] = depth[u] + 1;
            dfs(v, u);
        }
    }
}

int main() {
    ios::sync_with_stdio(false); cin.tie(0);
    cin >> n;
    for (int i = 0; i < n-1; ++i) {
        int a, b;
        cin >> a >> b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    for (int src = 1; src <= n; ++src) {
        if (adj[src].size() > 1) {
            depth[src] = 0;
            // debug(src);
            dfs(src, -1);
            break;
        }
    }
    sort(leaves.begin(), leaves.end(), [&] (int u, int v) {
        return depth[u] < depth[v];
    });
    // debug(leaves);
    int k = leaves.size();
    edges.emplace_back(leaves[0], leaves[k-1]);
    for (int i = 1; i <= k-2; i += 2) {
        edges.emplace_back(leaves[i], leaves[i+1]);
    }
    cout << edges.size() << '\n';
    for (auto &p : edges) {
        cout << p.first << ' ' << p.second << '\n';
    }
}

Subtask #1
0 / 18.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 12152 KB Output is correct
2 Correct 12 ms 12152 KB Output is correct
3 Correct 12 ms 12152 KB Output is correct
4 Correct 12 ms 12152 KB Output is correct
5 Correct 12 ms 12152 KB Output is correct
6 Correct 12 ms 12152 KB Output is correct
7 Correct 12 ms 12024 KB Output is correct
8 Correct 12 ms 12152 KB Output is correct
9 Correct 12 ms 12152 KB Output is correct
10 Correct 12 ms 12124 KB Output is correct
11 Correct 13 ms 12024 KB Output is correct
12 Correct 12 ms 12024 KB Output is correct
13 Correct 12 ms 12024 KB Output is correct
14 Correct 12 ms 12024 KB Output is correct
15 Incorrect 12 ms 12152 KB Breaking single line is causing network to disconnect.
16 Halted 0 ms 0 KB -

Subtask #2
0 / 45.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 12152 KB Output is correct
2 Correct 12 ms 12152 KB Output is correct
3 Correct 12 ms 12152 KB Output is correct
4 Correct 12 ms 12152 KB Output is correct
5 Correct 12 ms 12152 KB Output is correct
6 Correct 12 ms 12152 KB Output is correct
7 Correct 12 ms 12024 KB Output is correct
8 Correct 12 ms 12152 KB Output is correct
9 Correct 12 ms 12152 KB Output is correct
10 Correct 12 ms 12124 KB Output is correct
11 Correct 13 ms 12024 KB Output is correct
12 Correct 12 ms 12024 KB Output is correct
13 Correct 12 ms 12024 KB Output is correct
14 Correct 12 ms 12024 KB Output is correct
15 Incorrect 12 ms 12152 KB Breaking single line is causing network to disconnect.
16 Halted 0 ms 0 KB -

Subtask #3
0 / 37.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 12152 KB Output is correct
2 Correct 12 ms 12152 KB Output is correct
3 Correct 12 ms 12152 KB Output is correct
4 Correct 12 ms 12152 KB Output is correct
5 Correct 12 ms 12152 KB Output is correct
6 Correct 12 ms 12152 KB Output is correct
7 Correct 12 ms 12024 KB Output is correct
8 Correct 12 ms 12152 KB Output is correct
9 Correct 12 ms 12152 KB Output is correct
10 Correct 12 ms 12124 KB Output is correct
11 Correct 13 ms 12024 KB Output is correct
12 Correct 12 ms 12024 KB Output is correct
13 Correct 12 ms 12024 KB Output is correct
14 Correct 12 ms 12024 KB Output is correct
15 Incorrect 12 ms 12152 KB Breaking single line is causing network to disconnect.
16 Halted 0 ms 0 KB -