CSES - Aalto Competitive Programming 2024 - wk6 - Wed

CSES - Aalto Competitive Programming 2024 - wk6 - Wed - Results

Submission details
Task:	Fragile network
Sender:	aalto2024g_003
Submission time:	2024-10-09 17:43:31 +0300
Language:	C++ (C++20)
Status:	READY
Result:	RUNTIME ERROR

Test results
test	verdict	time
#1	ACCEPTED	0.01 s	details
#2	RUNTIME ERROR	0.01 s	details
#3	RUNTIME ERROR	0.01 s	details
#4	RUNTIME ERROR	0.01 s	details
#5	RUNTIME ERROR	0.01 s	details
#6	ACCEPTED	0.16 s	details
#7	RUNTIME ERROR	0.08 s	details
#8	TIME LIMIT EXCEEDED	--	details
#9	RUNTIME ERROR	0.08 s	details
#10	RUNTIME ERROR	0.08 s	details
#11	RUNTIME ERROR	0.01 s	details
#12	WRONG ANSWER	0.01 s	details
#13	WRONG ANSWER	0.01 s	details
#14	WRONG ANSWER	0.05 s	details
#15	RUNTIME ERROR	0.01 s	details
#16	WRONG ANSWER	0.01 s	details
#17	WRONG ANSWER	0.01 s	details
#18	RUNTIME ERROR	0.01 s	details
#19	WRONG ANSWER	0.01 s	details
#20	RUNTIME ERROR	0.01 s	details
#21	RUNTIME ERROR	0.01 s	details

Code

#include <bits/stdc++.h>
using namespace std;
 
#define int long long
 
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

string to_string(string s) {
    return '"' + s + '"';
}
 
string to_string(const char* s) {
    return to_string((string) s);
}
 
string to_string(bool b) {
    return (b ? "true" : "false");
}
 
template <typename A, typename B>
string to_string(pair<A, B> p) {
    return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
 
template <typename A>
string to_string(A v) {
    bool first = true;
    string res = "{";
    for (const auto &x : v) {
        if (!first) {
            res += ", ";
        }
        first = false;
        res += to_string(x);
    }
    res += "}";
    return res;
}
 
void debug_out() {
    cerr << endl;
}
 
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << " " << to_string(H);
    debug_out(T...);
}
 
#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

const int N = 1e5 + 5;
set<int> adj[N];
int n, nn;
set<int> alive;

void dfs(int u, int p) {
    if (sz(adj[u]) == 2 && p) {
        adj[p].erase(u);
        int v = *adj[u].begin();
        adj[v].erase(u);
        nn--;
        alive.erase(u);
        dfs(v, p);
    } else {
        for (int v : adj[u]) {
            if (v == p) continue;
            dfs(v, u);
        }
    }
}

signed main() {
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit); // RTE if input wrong datatype

    cin >> n;
    nn = n;
    for (int i = 1; i <= n; i++) alive.insert(i);
    for (int i = 1; i < n; i++) {
        int u, v;
        cin >> u >> v;
        adj[u].insert(v);
        adj[v].insert(u);
    }
    
    dfs(1, 0);

    if (sz(adj[1]) == 2) {
        int u = *adj[1].begin();
        int v = *next(adj[1].begin());
        adj[u].erase(1);
        adj[v].erase(1);
        adj[u].insert(v);
        adj[v].insert(u);
        nn--;
        alive.erase(1);
    }

    if (nn == 2) {
        cout << 1 << '\n';
        int u = *alive.begin();
        int v = *next(alive.begin());
        cout << u << ' ' << v << '\n';
    } else {
        int root = -1;
        for (int u : alive) {
            if (sz(adj[u]) > 1) {
                root = u;
                break;
            }
        }

        vector<pii> ans;
        vector<int> c(adj[root].begin(), adj[root].end());
        for (int i = 0; i + 1 < sz(c); i += 2) {
            ans.push_back({c[i], c[i + 1]});
        }
        if (sz(c) & 1) {
            ans.push_back({c[sz(c) - 2], c[sz(c) - 1]});
        }

        cout << sz(ans) << '\n';
        for (auto [u, v] : ans) cout << u << ' ' << v << '\n';
    }
}

Test details

Test 1

Verdict: ACCEPTED

input
`10 1 5 1 7 1 8 1 3 ...` view save

correct output
`5 5 2 7 9 8 6 3 10 ...` view save

user output
`5 2 3 4 5 6 7 8 9 ...` view save

Test 2

Verdict: RUNTIME ERROR

input
`10 4 5 3 4 2 3 9 10 ...` view save

correct output
`1 10 1` view save

user output
(empty)

Test 3

Verdict: RUNTIME ERROR

input
`10 1 8 1 3 3 5 5 7 ...` view save

correct output
`3 7 10 8 2 1 9` view save

user output
(empty)

Test 4

Verdict: RUNTIME ERROR

input
`10 1 5 3 7 2 10 3 8 ...` view save

correct output
`3 10 8 6 4 5 9` view save

user output
(empty)

Test 5

Verdict: RUNTIME ERROR

input
`10 4 8 3 4 4 6 2 3 ...` view save

correct output
`3 8 7 10 9 1 6` view save

user output
(empty)

Test 6

Verdict: ACCEPTED

input
`100000 1 56967 1 56618 1 42321 1 82550 ...` view save

correct output
`50000 56967 16911 56618 39942 42321 99902 82550 2538 ...` view save

user output
`50000 2 3 4 5 6 7 8 9 ...` Truncated

Test 7

Verdict: RUNTIME ERROR

input
`100000 92297 92298 23511 23512 68057 68058 65434 65435 ...` view save

correct output
`1 100000 1` view save

user output
(empty)

Test 8

Verdict: TIME LIMIT EXCEEDED

input
`100000 17747 97512 10397 12053 679 6975 4013 14565 ...` view save

correct output
`25057 92881 76094 20353 87429 16069 96487 71186 52809 ...` view save

user output
(empty)

Test 9

Verdict: RUNTIME ERROR

input
`100000 72941 72942 11232 11233 73464 73465 30042 30043 ...` view save

correct output
`489 16423 85168 20707 94190 36505 54940 96411 44067 ...` view save

user output
(empty)

Test 10

Verdict: RUNTIME ERROR

input
`100000 31451 31452 7473 7474 24056 24057 85181 85182 ...` view save

correct output
`51 25638 2983 87594 87371 92001 50610 46744 100000 ...` view save

user output
(empty)

Test 11

Verdict: RUNTIME ERROR

input
`10 1 2 1 3 3 4 3 5 ...` view save

correct output
`2 2 6 4 10` view save

user output
(empty)

Test 12

Verdict: WRONG ANSWER

input
`7 1 2 2 3 2 4 1 5 ...` view save

correct output
`2 4 7 3 6` view save

user output
`2 3 4 4 5` view save

Test 13

Verdict: WRONG ANSWER

input
`6 1 2 1 3 1 4 4 5 ...` view save

correct output
`2 3 6 2 5` view save

user output
`2 2 3 3 4` view save

Test 14

Verdict: WRONG ANSWER

input
`65538 1 2 1 3 1 4 3 5 ...` view save

correct output
`16385 34 36 40 42 35 41 48 50 ...` view save

user output
`2 2 3 3 4` view save

Test 15

Verdict: RUNTIME ERROR

input
`11 1 2 1 3 2 4 2 5 ...` view save

correct output
`2 9 11 8 10` view save

user output
(empty)

Test 16

Verdict: WRONG ANSWER

input
`7 1 2 1 3 2 4 2 5 ...` view save

correct output
`2 5 7 4 6` view save

user output
`2 3 4 4 5` view save

Test 17

Verdict: WRONG ANSWER

input
`7 1 2 1 3 2 4 2 5 ...` view save

correct output
`2 5 7 4 6` view save

user output
`2 3 4 4 5` view save

Test 18

Verdict: RUNTIME ERROR

input
`10 8 4 3 4 4 6 2 3 ...` view save

correct output
`3 8 7 10 9 1 6` view save

user output
(empty)

Test 19

Verdict: WRONG ANSWER

input
`7 1 2 1 5 2 3 2 6 ...` view save

correct output
`2 6 7 3 4` view save

user output
`2 3 5 5 6` view save

Test 20

Verdict: RUNTIME ERROR

input
`8 1 2 1 3 2 4 2 5 ...` view save

correct output
`3 4 7 6 8 1 5` view save

user output
(empty)

Test 21

Verdict: RUNTIME ERROR

input
`10 2 1 3 1 4 2 5 4 ...` view save

correct output
`3 9 8 6 10 3 7` view save

user output
(empty)

Aalto Competitive Programming 2024 - wk6 - Wed

Fragile network

Code

Test details

Test 1

Test 2

Test 3

Test 4

Test 5

Test 6

Test 7

Test 8

Test 9

Test 10

Test 11

Test 12

Test 13

Test 14

Test 15

Test 16

Test 17

Test 18

Test 19

Test 20

Test 21

Tasks

Submissions (aalto2024g_003)