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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 |
---|---|---|---|---|---|---|---|---|---|
#415610 | #6559. A Tree and Two Edges | ngpin04# | WA | 1499ms | 8880kb | C++14 | 5.7kb | 2024-05-21 05:42:23 | 2024-05-21 05:42:23 |
Judging History
answer
#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define lb lower_bound
#define pb push_back
#define bit(n) (1LL << (n))
#define getbit(x, i) (((x) >> (i)) & 1)
#define pii pair <int, int>
#define ALL(x) x.begin(), x.end()
using namespace std;
const int oo = 1e9;
const long long ooo = 1e18;
template<typename T1, typename T2> bool mini(T1 &a, T2 b) {
if (a > b) {
a = b;
return true;
}
return false;
}
template<typename T1, typename T2> bool maxi(T1 &a, T2 b) {
if (a < b) {
a = b;
return true;
}
return false;
}
const int lim = 5e4 + 5;
struct disjoint_set {
int h[lim], sz[lim];
disjoint_set() {
memset(h, -1, sizeof(h));
fill(sz, sz + lim, 1);
}
int fh(int nd) {
return h[nd] == -1 ? nd : h[nd] = fh(h[nd]);
}
bool same_par(int x, int y) {
return fh(x) == fh(y);
}
bool merge(int x, int y) {
x = fh(x), y = fh(y);
if(x != y) {
if(sz[x] < sz[y])
swap(x, y);
sz[x] += sz[y];
h[y] = x;
}
return x != y;
}
};
vector<int> edges[lim];
int disc[lim], low[lim], t;
vector<pair<int, int>> bridges;
void tarjan(int nd, int pr = -1) {
disc[nd] = low[nd] = t++;
for(auto x : edges[nd]) {
if(x == pr)
continue;
if(disc[x] == -1) {
tarjan(x, nd);
low[nd] = min(low[nd], low[x]);
}
else {
low[nd] = min(low[nd], disc[x]);
}
if(low[x] > disc[nd])
bridges.pb(mp(nd, x));
}
}
bool vis[lim];
void dfs(int nd, int origin, vector<pair<int, int>> &a) {
vis[nd] = 1;
a.pb(mp(nd, origin));
for(auto i : edges[nd]) {
if(!vis[i]) {
dfs(i, origin, a);
}
}
}
int main() {
memset(disc, -1, sizeof(disc));
memset(low, -1, sizeof(low));
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, q;
cin >> n >> q;
vector<pair<int, int>> adj;
for(int i = 1; i <= n + 1; ++i) {
int u, v;
cin >> u >> v;
edges[u].pb(v);
edges[v].pb(u);
adj.pb(mp(u, v));
}
tarjan(1);
// cerr << "bridge cnt: " << bridges.size() << endl;
for(auto &p : bridges) {
if(p.fi > p.se)
swap(p.fi, p.se);
// cerr << p.fi << " " << p.se << endl;
}
sort(bridges.begin(), bridges.end());
disjoint_set dsu;
for(auto p : adj) {
if(p.fi > p.se)
swap(p.fi, p.se);
if(!binary_search(bridges.begin(), bridges.end(), p)) {
// not bridge
dsu.merge(p.fi, p.se);
}
}
// nbd -> non bridge degree
int nbd[n + 1];
memset(nbd, 0, sizeof(nbd));
// cerr << "nbd" << endl;
for(int i = 1; i <= n; ++i) {
for(auto x : edges[i]) {
if(dsu.same_par(i, x)) {
++nbd[i];
}
}
// cerr << nbd[i] << " ";
}
// cerr << endl;
for(int i = 1; i <= n; ++i)
edges[i].clear();
for(auto p : adj) {
if(p.fi > p.se)
swap(p.fi, p.se);
if(binary_search(bridges.begin(), bridges.end(), p)) {
// bridge
edges[p.fi].pb(p.se);
edges[p.se].pb(p.fi);
}
}
// fi -> node to find
// se -> last node in the important cc
vector<vector<pair<int, int>>> v;
bool used[n + 1];
memset(used, 0, sizeof(used));
for(int i = 1; i <= n; ++i) {
// cerr << dsu.fh(i) << " " << dsu.sz[dsu.fh(i)] << endl;
if(dsu.sz[dsu.fh(i)] > 1 && !used[dsu.fh(i)]) {
// cerr << "dfs " << i << endl;
vector<pair<int, int>> cur;
used[dsu.fh(i)] = 1;
// find for every other node the original
memset(vis, 0, sizeof(vis));
for(int j = 1; j <= n; ++j) {
if(dsu.fh(j) == dsu.fh(i))
dfs(j, j, cur);
}
sort(cur.begin(), cur.end());
v.pb(cur);
}
}
for(int i = 1; i <= n; ++i) {
if(nbd[i] == 4) {
// special special case
int spec = i;
disjoint_set dsu;
for(auto p : adj) {
if(p.fi != i && p.se != i)
dsu.merge(p.fi, p.se);
}
while(q--) {
int x, y;
cin >> x >> y;
int res = 1;
for(auto vec : v) {
int ndx = (*lb(vec.begin(), vec.end(), mp(x, 0))).se, ndy = (*lb(vec.begin(), vec.end(), mp(y, 0))).se;
// cerr << x << " " << y << " " << ndx << " " << ndy << endl;
if(ndx == ndy)
res *= 1;
else if(nbd[ndx] == 4 || nbd[ndy] == 4 || dsu.same_par(x, y))
res *= 2;
else
res *= 4;
}
cout << res << endl;
}
exit(0);
}
}
while(q--) {
int x, y;
cin >> x >> y;
int res = 1;
for(auto vec : v) {
int ndx = (*lb(vec.begin(), vec.end(), mp(x, 0))).se, ndy = (*lb(vec.begin(), vec.end(), mp(y, 0))).se;
// cerr << ndx << " " << ndy << endl;
if(ndx == ndy)
res *= 1;
else if(nbd[ndx] == 3 || nbd[ndy] == 3)
res *= 3;
else if(v.size() == 1)
res *= 4;
else
res *= 2;
}
cout << res << endl;
}
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 2ms
memory: 6052kb
input:
4 6 1 2 1 3 1 4 2 3 2 4 1 2 1 3 1 4 2 3 2 4 3 4
output:
3 3 3 3 3 4
result:
ok 6 lines
Test #2:
score: 0
Accepted
time: 2ms
memory: 5896kb
input:
6 4 1 2 1 3 1 6 2 3 3 4 3 5 4 5 1 2 1 3 1 4 1 6
output:
2 2 4 1
result:
ok 4 lines
Test #3:
score: -100
Wrong Answer
time: 1499ms
memory: 8880kb
input:
50000 50000 11561 23122 14261 28523 24407 48814 17947 35894 14803 29607 19557 39115 12415 24830 9583 19167 18397 36794 439 878 18040 36080 17150 34300 7922 15845 18938 37877 18625 37250 6459 12919 9818 19636 3579 7158 21323 42646 23882 47764 13603 27207 8353 16707 15907 31814 20935 41871 11686 23372...
output:
4 4 4 4 4 4 1 4 4 1 4 4 4 4 4 4 1 4 4 4 4 4 4 4 4 4 4 4 4 4 1 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 1 4 1 1 4 4 4 4 4 4 1 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 1 4 4 4 4 4 4 4 4 4 4 1 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 1 4 4 4 4 4 4 4 ...
result:
wrong answer 2nd lines differ - expected: '3', found: '4'