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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 |
---|---|---|---|---|---|---|---|---|---|
#101833 | #3846. Link-Cut Tree | Register_int | AC ✓ | 233ms | 8732kb | C++14 | 1.4kb | 2023-05-01 12:43:16 | 2023-05-01 12:43:18 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 1e5 + 10;
const int mod = 998244353;
struct edge {
int v, nxt;
} e[MAXN << 1];
int head[MAXN], tot = 1;
inline
void add(int u, int v) {
e[++tot] = { v, head[u] }, head[u] = tot;
}
int fa[MAXN];
int find(int k) {
return k == fa[k] ? k : fa[k] = find(fa[k]);
}
inline
bool merge(int u, int v) {
return (u = find(u)) != (v = find(v)) && (fa[u] = v);
}
int pre[MAXN], id[MAXN];
int ans[MAXN], cnt, rt;
void init(int u) {
if (!id[u]) rt = u;
for (int i = head[u], v; i; i = e[i].nxt) {
if ((i >> 1) == id[u]) continue; v = e[i].v;
pre[v] = u, id[v] = i >> 1, init(v);
}
}
inline
void solve(int u) {
for (cnt = 0; u != rt; u = pre[u]) ans[++cnt] = id[u];
}
inline
void clear(int n) {
for (int i = 1; i <= n; i++) head[i] = id[i] = pre[i] = 0; tot = 1;
}
int t, n, m, u[MAXN], v[MAXN];
int main() {
for (scanf("%d", &t); t--; clear(n)) {
scanf("%d%d", &n, &m), rt = 0;
for (int i = 1; i <= m; i++) scanf("%d%d", &u[i], &v[i]);
for (int i = 1; i <= n; i++) fa[i] = i;
for (int i = 1; i <= m; i++) {
if (!merge(u[i], v[i])) { init(u[i]), solve(v[i]), ans[++cnt] = i; break; }
add(u[i], v[i]), add(v[i], u[i]);
}
if (!rt) { puts("-1"); continue; } sort(ans + 1, ans + cnt + 1);
for (int i = 1; i <= cnt; i++) printf("%d%c", ans[i], " \n"[i == cnt]);
}
}
详细
Test #1:
score: 100
Accepted
time: 0ms
memory: 3632kb
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: 117ms
memory: 7748kb
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: 233ms
memory: 8732kb
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