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QOJ
ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#72227 | #3846. Link-Cut Tree | neko_nyaa# | AC ✓ | 217ms | 22460kb | C++23 | 1.9kb | 2023-01-15 10:23:15 | 2023-01-15 10:23:18 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
#define int long long
struct DSU {
vector<int> P, S;
DSU(int n) {
P.resize(n+1);
S.resize(n+1, 1);
for (int i = 1; i <= n; i++) P[i] = i;
}
int find(int x) {
if (x == P[x]) return x;
return P[x] = find(P[x]);
}
bool merge(int a, int b) {
a = find(a); b = find(b);
if (a == b) return 0;
if (S[a] < S[b]) swap(a, b);
S[a] += S[b];
P[b] = a;
return 1;
}
int same(int a, int b) {
return find(a) == find(b);
}
};
int par[100001], pid[100001], hei[100001];
vector<pair<int, int>> adj[100001];
void dfs(int now, int prv, int h, int pri) {
hei[now] = h;
par[now] = prv;
pid[now] = pri;
for (auto [u, i]: adj[now]) {
if (u != prv) {
dfs(u, now, h+1, i);
}
}
}
void solve() {
int n, m; cin >> n >> m;
DSU d(n); vector<tuple<int, int, int>> e;
bool f = 0;
for (int i = 1; i <= m; i++) {
int x, y; cin >> x >> y;
if (f) continue;
e.emplace_back(x, y, i);
if (!d.merge(x, y)) f = 1;
}
if (!f) {
cout << "-1\n";
return;
}
auto [p, q, id1] = e.back(); e.pop_back();
for (int i = 1; i <= n; i++) {
adj[i].clear(); par[i] = hei[i] = pid[i] = 0;
}
for (auto [u, v, i]: e) {
adj[u].emplace_back(v, i);
adj[v].emplace_back(u, i);
}
for (int i = 1; i <= n; i++) {
if (par[i] == 0) {
dfs(i, i, 1, 0);
}
}
vector<int> ans; ans.push_back(id1);
if (hei[p] < hei[q]) swap(p, q);
while (hei[p] > hei[q]) {
ans.push_back(pid[p]);
p = par[p];
}
while (p != q) {
ans.push_back(pid[p]);
p = par[p];
ans.push_back(pid[q]);
q = par[q];
}
sort(ans.begin(), ans.end());
for (int i = 0; i < ans.size(); i++) {
cout << ans[i];
if (i+1 == ans.size()) {
cout << "\n";
} else {
cout << ' ';
}
}
}
signed main() {
ios::sync_with_stdio(0); cin.tie(0);
int t; cin >> t;
while (t--) {
solve();
}
return 0;
}
詳細信息
Test #1:
score: 100
Accepted
time: 2ms
memory: 6744kb
input:
2 6 8 1 2 2 3 5 6 3 4 2 5 5 4 5 1 4 2 4 2 1 2 4 3
output:
2 4 5 6 -1
result:
ok 2 lines
Test #2:
score: 0
Accepted
time: 217ms
memory: 21404kb
input:
1658 9 20 6 4 5 8 1 7 2 3 3 8 3 1 4 8 5 3 7 6 1 6 4 9 4 1 9 3 2 5 4 5 8 9 1 8 4 2 5 7 3 6 14 78 13 12 10 8 2 10 6 13 2 14 13 1 14 10 9 6 2 13 8 3 9 8 5 6 14 12 8 1 9 14 9 5 12 6 5 10 3 12 10 4 8 5 9 10 6 8 1 6 12 4 3 13 1 5 10 3 13 9 10 13 2 5 4 7 7 1 7 6 9 3 2 12 1 10 9 1 1 14 3 1 3 4 11 1 11 6 7 1...
output:
2 5 8 3 5 7 1 3 4 2 3 4 2 3 4 7 13 1 3 4 5 9 3 4 7 12 1 2 3 8 10 11 2 3 5 7 12 13 14 15 16 1 2 3 5 1 2 4 1 3 4 1 2 3 1 2 3 10 11 15 1 5 6 1 5 7 1 2 3 4 -1 1 3 6 -1 1 2 3 5 -1 -1 6 8 9 10 11 16 1 2 6 2 3 4 -1 -1 7 8 12 13 18 -1 1 4 8 12 3 5 10 4 6 8 1 2 3 4 3 5 6 5 8 10 15 4 6 8 -1 1 2 3 5 6 1 3 4 1 ...
result:
ok 1658 lines
Test #3:
score: 0
Accepted
time: 213ms
memory: 22460kb
input:
10 100000 100000 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 11 11 12 12 13 13 14 14 15 15 16 16 17 17 18 18 19 19 20 20 21 21 22 22 23 23 24 24 25 25 26 26 27 27 28 28 29 29 30 30 31 31 32 32 33 33 34 34 35 35 36 36 37 37 38 38 39 39 40 40 41 41 42 42 43 43 44 44 45 45 46 46 47 47 48 48 49 49 50 50 51 ...
output:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 ...
result:
ok 10 lines