#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> pii;
const int inf = 1e9;
class Query {
public:
bool type; // 0 = query, 1 = count
int x, y, time;
Query(bool t, int time, int x, int y=-1) : type(t), time(time), x(x), y(y) {}
Query() {}
};
const int MAXN = 12e4;
const int MX_jump = 17;
vector<pii> edges[MAXN]; // node, time
pii lca[MAXN][MX_jump];
pii lca_rev[MAXN][MX_jump];
int lca_node[MAXN][MX_jump];
pii edge_list[MAXN];
Query queries[MAXN];
int depth[MAXN];
vector<int> cent_graph[MAXN];
int cent_par[MAXN];
bool vis[MAXN];
int sz[MAXN];
int rt;
int n, q, t = 0, p = 0;
void dfs_lca(int cur = 0, int p = -1) {
for (pii e: edges[cur]) {
if (e.first == p) continue;
depth[e.first] = 1+depth[cur];
dfs_lca(e.first, cur);
lca_node[e.first][0] = cur;
lca[e.first][0] = pii(e.second, e.second);
lca_rev[e.first][0] = pii(e.second, e.second);
} // confirmed
}
pii combine(pii a, pii b) {
if (b == pii(-2, -2)) return a;
if (a == pii(-2, -2)) return b;
if (b.first <= a.second) return pii(-1, inf);
return pii(a.first, b.second); // confirmed
}
void make_lca() {
for (int i = 1; i < MX_jump; i++) {
for (int j = 0; j < n; j++) {
lca_node[j][i] = lca_node[lca_node[j][i-1]][i-1];
lca[j][i] = combine(lca[j][i-1], lca[lca_node[j][i-1]][i-1]);
lca_rev[j][i] = combine(lca_rev[lca_node[j][i-1]][i-1], lca_rev[j][i-1]);
}
} // confirmed
}
pair<pii, pii> get_path(int a, int b) { // a != b
pii a_path = pii(-2, -2);
pii b_path = pii(-2, -2);
int d = depth[a]-depth[b];
int pow = 0;
while (d > 0) {
if (d & 1) {
a_path = combine(a_path, lca[a][pow]);
a = lca_node[a][pow];
}
pow++;
d /= 2;
}
d = depth[b]-depth[a];
pow = 0;
while (d > 0) {
if (d & 1) {
b_path = combine(lca_rev[b][pow], b_path);
b = lca_node[b][pow];
}
pow++;
d /= 2;
}
for (int i = MX_jump-1; i >= 0; i--) {
if (lca_node[a][i] != lca_node[b][i]) {
a_path = combine(a_path, lca[a][i]);
b_path = combine(lca_rev[b][i], b_path);
a = lca_node[a][i];
b = lca_node[b][i];
}
}
if (a != b) {
a_path = combine(a_path, lca[a][0]);
b_path = combine(lca_rev[b][0], b_path);
}
return pair<pii, pii>(a_path, b_path);
}
bool is_path(int a, int b, int t) {
pair<pii, pii> v = get_path(a, b);
return v.first.second < v.second.first && v.second.second < t;
}
int path_end(int a, int b) {
pair<pii, pii> v = get_path(a, b);
return combine(v.first, v.second).second;
}
void make_sz(int cur, int p = -1) {
sz[cur] = 1;
for (pii e: edges[cur]) {
int nxt = e.first;
if (nxt == p || vis[nxt]) continue;
make_sz(nxt, cur);
sz[cur] += sz[nxt];
}
}
int cent_dec(int cur) {
make_sz(cur);
int tot = sz[cur];
bool next_found = 1;
int p = -1;
while (next_found) {
next_found = 0;
for (pii e: edges[cur]) {
int nxt = e.first;
if (nxt == p || vis[nxt]) continue;
if (sz[nxt] > tot/2) {
p = cur;
cur = nxt;
next_found = 1;
break;
}
}
}
vis[cur] = 1;
for (pii e: edges[cur]) {
if (!vis[e.first]) {
int c = cent_dec(e.first);
cent_graph[cur].push_back(c);
cent_par[c] = cur;
}
}
return cur;
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(NULL);
cin >> n >> q;
for (int i = 0; i < n+q-1; i++) {
int a, b;
char c; cin >> c >> a;
a--;
if (c == 'S') {
cin >> b; b--;
edge_list[t] = pii(a, b);
edges[a].push_back(pii(b, t));
edges[b].push_back(pii(a, t));
t++;
}
else if (c == 'Q') {
cin >> b; b--;
queries[p++] = Query(0, i-p, a, b);
}
else queries[p++] = Query(1, i-p, a);
}
dfs_lca();
make_lca();
rt = cent_dec(0);
for (int i = 0; i < q; i++) {
if (queries[i].type) {
cout << "0\n";
}
else {
if (is_path(queries[i].y, queries[i].x, queries[i].time)) cout << "yes\n";
else cout << "no\n";
}
}
}
Compilation message
servers.cpp: In constructor 'Query::Query(bool, int, int, int)':
servers.cpp:11:12: warning: 'Query::time' will be initialized after [-Wreorder]
11 | int x, y, time;
| ^~~~
servers.cpp:11:6: warning: 'int Query::x' [-Wreorder]
11 | int x, y, time;
| ^
servers.cpp:12:2: warning: when initialized here [-Wreorder]
12 | Query(bool t, int time, int x, int y=-1) : type(t), time(time), x(x), y(y) {}
| ^~~~~
servers.cpp: In function 'int main()':
servers.cpp:164:13: warning: operation on 'p' may be undefined [-Wsequence-point]
164 | queries[p++] = Query(0, i-p, a, b);
| ~^~
servers.cpp:164:13: warning: operation on 'p' may be undefined [-Wsequence-point]
servers.cpp:166:17: warning: operation on 'p' may be undefined [-Wsequence-point]
166 | else queries[p++] = Query(1, i-p, a);
| ~^~
servers.cpp:166:17: warning: operation on 'p' may be undefined [-Wsequence-point]
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
27 ms |
8140 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
27 ms |
8140 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
25 ms |
8244 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
25 ms |
8244 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
29 ms |
8184 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
29 ms |
8184 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
28 ms |
8148 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
28 ms |
8148 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
34 ms |
8140 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
34 ms |
8140 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
28 ms |
8188 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
28 ms |
8188 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
