#include <cstdio>
#include <vector>
#include <algorithm>
#define X first
#define Y second
#define PB push_back
using namespace std;
const int N = 120500;
const int LOG = 17;
vector < int > v[N], poc[N], zav[N], sm[35 * N];
int n, q, st[N], en[N], bio[35 * N], dep[N], par[N][LOG];
int dp[N][LOG][2], cv[N];
void dfs(int x, int lst){
dep[x] = dep[lst] + 1;
par[x][0] = lst;
for(int y : v[x])
if(y != lst) dfs(y, x);
}
int naso = 0, node = 1;
void make_node(int i, int j, int k){
if(dp[i][j][k]) return;
dp[i][j][k] = node++;
make_node(i, j - 1, k);
make_node(par[i][j - 1], j - 1, k);
if(!k){
sm[dp[i][j][k]].PB(dp[i][j - 1][k]);
sm[dp[i][j][k]].PB(dp[par[i][j - 1]][j - 1][k]);
}
else{
sm[dp[i][j - 1][k]].PB(dp[i][j][k]);
sm[dp[par[i][j - 1]][j - 1][k]].PB(dp[i][j][k]);
}
}
int digni(int a, int k){
for(int j = 0;j < LOG;j++)
if(k & (1 << j)) a = par[a][j];
return a;
}
int lca(int a, int b){
if(dep[a] < dep[b]) swap(a, b);
a = digni(a, dep[a] - dep[b]);
if(a == b) return a;
for(int j = LOG - 1;j >= 0;j--)
if(par[a][j] != par[b][j])
a = par[a][j], b = par[b][j];
return par[a][0];
}
void oznaci(int a, int b, int k, int tko){
if(dep[a] < dep[b]) swap(a, b);
for(int j = LOG - 1;j >= 0;j--){
if(dep[a] - dep[b] >= (1 << j)){
make_node(a, j, k);
if(!k) sm[tko].PB(dp[a][j][k]);
else sm[dp[a][j][k]].PB(tko);
a = par[a][j];
}
}
if(a == b) return;
for(int j = LOG - 1;j >= 0;j--){
if(par[a][j] != par[b][j]){
make_node(a, j, k); make_node(b, j, k);
if(!k)
sm[tko].PB(dp[a][j][k]),
sm[tko].PB(dp[b][j][k]);
else
sm[dp[a][j][k]].PB(tko),
sm[dp[b][j][k]].PB(tko);
a = par[a][j], b = par[b][j];
}
}
return;
}
void ciklus(int x){
if(bio[x] == 1) { naso = 1; }
if(bio[x]) return;
bio[x] = 1;
for(int y : sm[x]){
ciklus(y);
}
bio[x] = 2;
}
void solve(){
scanf("%d", &n);
for(int i = 1;i < n;i++){
int a, b; scanf("%d%d", &a, &b);
v[a].PB(b);
v[b].PB(a);
}
dfs(1, 1);
for(int j = 1;j < LOG;j++){
for(int i = 1;i <= n;i++){
dp[i][j][0] = 0, dp[i][j][1] = 0;
par[i][j] = par[par[i][j - 1]][j - 1];
}
}
scanf("%d", &q);
for(int i = 0;i < q;i++){
int a, b; scanf("%d%d", &a, &b);
st[i] = a; en[i] = b; cv[i] = node++;
poc[a].PB(i); zav[b].PB(i);
}
for(int i = 1;i <= n;i++){
dp[i][0][0] = node++;
dp[i][0][1] = node++;
for(int x : poc[i])
sm[dp[i][0][0]].PB(cv[x]);
for(int x : zav[i])
sm[cv[x]].PB(dp[i][0][1]);
}
for(int i = 0;i < q;i++){
int a = st[i], b = en[i];
int lc = lca(a, b);
if(lc != a && lc != b){
oznaci(par[a][0], b, 0, cv[i]);
oznaci(a, par[b][0], 1, cv[i]);
}
else if(lc == a){
oznaci(digni(b, dep[b] - dep[a] - 1), b, 0, cv[i]);
oznaci(a, par[b][0], 1, cv[i]);
}
else{
oznaci(par[a][0], b, 0, cv[i]);
oznaci(a, digni(a, dep[a] - dep[b] - 1), 1, cv[i]);
}
}
for(int i = 1;i < node;i++) ciklus(i);
for(int i = 1;i < node;i++) bio[i] = 0, sm[i].clear();
for(int i = 1;i <= n;i++) v[i].clear(), poc[i].clear(), zav[i].clear();
printf(naso ? "No\n" : "Yes\n");
naso = 0; node = 1;
}
int main(){
int T; scanf("%d", &T);
for(;T--;) solve();
return 0;
}
Compilation message
jail.cpp: In function 'void solve()':
jail.cpp:95:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
95 | scanf("%d", &n);
| ~~~~~^~~~~~~~~~
jail.cpp:97:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
97 | int a, b; scanf("%d%d", &a, &b);
| ~~~~~^~~~~~~~~~~~~~~~
jail.cpp:108:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
108 | scanf("%d", &q);
| ~~~~~^~~~~~~~~~
jail.cpp:110:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
110 | int a, b; scanf("%d%d", &a, &b);
| ~~~~~^~~~~~~~~~~~~~~~
jail.cpp: In function 'int main()':
jail.cpp:147:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
147 | int T; scanf("%d", &T);
| ~~~~~^~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
51 ms |
107784 KB |
Output is correct |
2 |
Correct |
53 ms |
107740 KB |
Output is correct |
3 |
Incorrect |
51 ms |
107720 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
49 ms |
107804 KB |
Output is correct |
2 |
Incorrect |
51 ms |
107740 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
49 ms |
107804 KB |
Output is correct |
2 |
Incorrect |
51 ms |
107740 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
49 ms |
107804 KB |
Output is correct |
2 |
Incorrect |
51 ms |
107740 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
49 ms |
107804 KB |
Output is correct |
2 |
Incorrect |
51 ms |
107740 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
58 ms |
107772 KB |
Output is correct |
2 |
Correct |
51 ms |
107820 KB |
Output is correct |
3 |
Correct |
53 ms |
107780 KB |
Output is correct |
4 |
Incorrect |
59 ms |
107792 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
51 ms |
107784 KB |
Output is correct |
2 |
Correct |
53 ms |
107740 KB |
Output is correct |
3 |
Incorrect |
51 ms |
107720 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |