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답안 #594548

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
594548 2022-07-12T16:25:54 Z bogdanvladmihai Pipes (BOI13_pipes) C++14
35 / 100
 349 ms 35768 KB 
#include <bits/stdc++.h>
using namespace std;

#define int long long

/***
N equations and M unknowns - can only have a unique solution if M <= N
Since M >= N - 1 =>
* the graph is a tree, in wich case we can solve the problem
* the graph is a tree with a simple cycle (N edges). Solve the problem for leafs and solve from a cycle

Solve for a cycle:
* even length: multiple solution (for each node do +1 on one edge and -1 on the other)
* odd length: unique solution, do some math stuff and deduce first edge

N = the number of nodes that are left are the process

sum(1) = W(n, 1) + W(1, 2)
sum(2) = W(1, 2) + W(2, 3)

sum(1) = W(n, 1) + sum(2) - W(2, 3)
sum(1) = W(n, 1) + sum(2) - sum(3) + sum(4) - ... - sum(N) + W(n, 1)
2 * W(n, 1) = sum(1) - sum(2) + sum(3) - sum(4) + .... + sum(N)

***/

const int MAXN = 1000 * 100;

int n, m;
set<int> g[MAXN + 1];
pair<int, int> edges[MAXN + 1];
map<pair<int, int>, int> edgeId;
int weight[MAXN + 1], sum[MAXN + 1];
bool visited[MAXN + 1];

vector<int> cycle;
void dfs(int u, int dad = -1) {
    visited[u] = true;
    cycle.push_back(u);

    for (const int &v : g[u]) {
        if (v == dad || visited[v]) {
            continue;
        }

        dfs(v, u);
    }
}

signed main() {
    cin >> n >> m;

    if (m > n) {
        cout << "0\n";
        return 0;
    }

    for (int i = 1; i <= n; i++) {
        cin >> sum[i];
    }
    for (int i = 0; i < m; i++) {
        int u, v; cin >> u >> v;

        edgeId[make_pair(u, v)] = edgeId[make_pair(v, u)] = i;

        g[u].insert(v);
        g[v].insert(u);
    }

    queue<int> q;
    for (int i = 1; i <= n; i++) {
        if ((int)g[i].size() == 1) {
            q.push(i);
        }
    }

    while (!q.empty()) {
        int u = q.front();
        q.pop();

        if ((int)g[u].size() > 0) {
            int v = *g[u].begin();
            int id = edgeId[make_pair(u, v)];

            weight[id] = sum[u];
            sum[v] -= weight[id];

            g[u].erase(v);
            g[v].erase(u);
            if ((int)g[v].size() == 1) {
                q.push(v);
            }
        }
    }

    for (int i = 0; i < m; i++) {
        cout << 2 * weight[i] << " ";
    }
    cout << "\n";

    for (int i = 1; i <= n; i++) {
        if ((int)g[i].size() > 0) {
            dfs(i);
            break;
        }
    }

    if ((int)cycle.size() > 0 && (int)cycle.size() % 2 == 0) {
        cout << "0\n";
        return 0;
    }

    if ((int)cycle.size() > 0) {
        int s = 0;
        for (int i = 0; i < (int)cycle.size(); i++) {
            if (i % 2 == 0) {
                s += sum[cycle[i]];
            } else {
                s -= sum[cycle[i]];
            }
        }

        int id = edgeId[make_pair(cycle[0], cycle.back())];

        weight[id] = s / 2;

        g[cycle[0]].erase(cycle.back());
        g[cycle.back()].erase(cycle[0]);

        sum[cycle[0]] -= weight[id];
        sum[cycle.back()] -= weight[id];

        q.push(cycle[0]);
      //  q.push(cycle.back());
        while (!q.empty()) {
            int u = q.front();
            q.pop();

            int v = *g[u].begin();
            int id = edgeId[make_pair(u, v)];

            weight[id] = sum[u];
            sum[v] -= weight[id];

            g[u].erase(v);
            g[v].erase(u);
            if ((int)g[v].size() == 1) {
                q.push(v);
            }
        }
    }

    for (int i = 0; i < m; i++) {
        cout << 2 * weight[i] << " ";
    }
    cout << "\n";

    return 0;
}

Subtask #1
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 4 ms 4948 KB Output isn't correct
2 Incorrect 4 ms 5012 KB Output isn't correct
3 Incorrect 4 ms 5204 KB Output isn't correct
4 Incorrect 314 ms 29792 KB Output isn't correct
5 Incorrect 4 ms 4948 KB Output isn't correct
6 Incorrect 3 ms 5016 KB Output isn't correct
7 Incorrect 3 ms 4988 KB Output isn't correct
8 Incorrect 4 ms 4948 KB Output isn't correct
9 Incorrect 5 ms 5148 KB Output isn't correct
10 Incorrect 4 ms 5204 KB Output isn't correct
11 Incorrect 5 ms 5204 KB Output isn't correct
12 Incorrect 4 ms 5204 KB Output isn't correct
13 Incorrect 227 ms 24812 KB Output isn't correct
14 Incorrect 272 ms 28536 KB Output isn't correct
15 Incorrect 278 ms 29964 KB Output isn't correct
16 Incorrect 249 ms 26188 KB Output isn't correct
17 Incorrect 279 ms 29972 KB Output isn't correct
18 Incorrect 308 ms 29956 KB Output isn't correct
19 Incorrect 284 ms 29544 KB Output isn't correct
20 Incorrect 3 ms 4948 KB Output isn't correct
21 Incorrect 4 ms 5148 KB Output isn't correct
22 Incorrect 278 ms 29908 KB Output isn't correct
23 Incorrect 253 ms 24844 KB Output isn't correct
24 Incorrect 287 ms 30020 KB Output isn't correct
25 Incorrect 228 ms 25844 KB Output isn't correct

Subtask #2
35.0 / 70.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 3 ms 4948 KB Output isn't correct
2 Incorrect 4 ms 5332 KB Output isn't correct
3 Incorrect 299 ms 31100 KB Output isn't correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 2 ms 4948 KB Output is correct
6 Correct 3 ms 4948 KB Output is correct
7 Incorrect 3 ms 4948 KB Output isn't correct
8 Incorrect 3 ms 4948 KB Output isn't correct
9 Incorrect 3 ms 4948 KB Output isn't correct
10 Correct 3 ms 4948 KB Output is correct
11 Correct 3 ms 4948 KB Output is correct
12 Correct 3 ms 4948 KB Output is correct
13 Correct 3 ms 4948 KB Output is correct
14 Incorrect 3 ms 4948 KB Output isn't correct
15 Incorrect 6 ms 5332 KB Output isn't correct
16 Incorrect 5 ms 5204 KB Output isn't correct
17 Incorrect 6 ms 5264 KB Output isn't correct
18 Correct 4 ms 4948 KB Output is correct
19 Correct 3 ms 5016 KB Output is correct
20 Correct 3 ms 5024 KB Output is correct
21 Correct 3 ms 4948 KB Output is correct
22 Incorrect 4 ms 5204 KB Output isn't correct
23 Incorrect 235 ms 28936 KB Output isn't correct
24 Incorrect 324 ms 33352 KB Output isn't correct
25 Incorrect 282 ms 31120 KB Output isn't correct
26 Correct 3 ms 5024 KB Output is correct
27 Correct 3 ms 4948 KB Output is correct
28 Correct 3 ms 4948 KB Output is correct
29 Correct 3 ms 4948 KB Output is correct
30 Incorrect 305 ms 32324 KB Output isn't correct
31 Incorrect 349 ms 35768 KB Output isn't correct
32 Incorrect 321 ms 31060 KB Output isn't correct
33 Incorrect 285 ms 33204 KB Output isn't correct
34 Correct 3 ms 4948 KB Output is correct
35 Correct 3 ms 5024 KB Output is correct
36 Correct 3 ms 4948 KB Output is correct
37 Correct 3 ms 4948 KB Output is correct
38 Incorrect 307 ms 33064 KB Output isn't correct
39 Incorrect 327 ms 30492 KB Output isn't correct
40 Incorrect 315 ms 33140 KB Output isn't correct
41 Incorrect 272 ms 35268 KB Output isn't correct
42 Correct 3 ms 4948 KB Output is correct
43 Correct 3 ms 4948 KB Output is correct
44 Correct 3 ms 4948 KB Output is correct
45 Correct 3 ms 4948 KB Output is correct
46 Incorrect 308 ms 32500 KB Output isn't correct
47 Incorrect 319 ms 33328 KB Output isn't correct
48 Incorrect 296 ms 35596 KB Output isn't correct
49 Incorrect 264 ms 29008 KB Output isn't correct
50 Correct 3 ms 4948 KB Output is correct
51 Correct 4 ms 4948 KB Output is correct
52 Correct 3 ms 5024 KB Output is correct
53 Correct 3 ms 5024 KB Output is correct
54 Incorrect 316 ms 31984 KB Output isn't correct