#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll MOD = 1000000007;
ll mpow(ll x, ll y){
if(!y) return 1;
if(y%2) return mpow(x, y-1) * x % MOD;
ll tmp = mpow(x, y/2);
return tmp*tmp%MOD;
}
int n;
ll k;
vector<int> link[100002];
int depth[100002];
int DP[100002];
int DProot[100002];
ll ans;
void dfs(int x, int p=-1){
for(auto y: link[x]){
if(y==p) continue;
depth[y] = depth[x] + 1;
dfs(y, x);
if(!DP[y]) DP[x] = 1;
}
}
void dfs2(int x, int p=-1, bool winUp = 0){
DProot[x] = (DP[x] || winUp);
int cnt = 0;
for(auto y: link[x]) if(y!=p) cnt += !DP[y];
for(auto y: link[x]){
if(y==p) continue;
dfs2(y, x, !winUp && !(cnt-!DP[y]));
}
}
int dfsFind(int x, int p=-1){ /// ������ ������ �ϴ� ��� ���� �� ���� ã��
if(depth[x] % 2 == 0){ /// my turn
int cnt = 0;
for(auto y: link[x]){
if(y!=p && !DP[y]) cnt++;
}
if(cnt > 1) return 0;
assert(cnt == 1);
for(auto y: link[x]){
if(y!=p && !DP[y]) return dfsFind(y, x);
}
exit(1);
}
else{ /// your turn
int ret = 1;
for(auto y: link[x]){
if(y==p) continue;
ret += dfsFind(y, x);
}
return ret;
}
}
int dfsFind2(int x, int p=-1){
if(depth[x] % 2 == 0){ /// my turn
int ret = 1;
for(auto y: link[x]){
if(y==p) continue;
ret += dfsFind2(y, x);
}
return ret;
}
else{ /// your turn
int cnt = 0;
for(auto y: link[x]){
if(y!=p && !DP[y]) cnt++;
}
if(cnt > 1) return 0;
assert(cnt == 1);
for(auto y: link[x]){
if(y!=p && !DP[y]) return dfsFind2(y, x);
}
exit(1);
}
}
int main(){
scanf("%d %lld", &n, &k);
for(int i=1; i<n; i++){
int x, y;
scanf("%d %d", &x, &y);
link[x].push_back(y);
link[y].push_back(x);
}
// dfs(1);
// dfs2(1);
for(int i=n; i>=1; i--){
for(int x=0; x<=n+1; x++) depth[x] = DP[x] = 0;
dfs(i), DProot[i] = DP[i];
}
// for(int i=1; i<=n; i++) printf("%d ", DProot[i]);
if(DP[1]){ /// ���������� �̱� ��
ll W = 0; /// ? -> W
for(int i=1; i<=n; i++) if(DProot[i]) W++;
ans += W*n;
ll myturn = 0; /// my turn -> L
for(int i=1; i<=n; i++) if(depth[i] % 2 == 0) myturn++;
ans += myturn * (n-W);
ll dw = 0;
for(int i=1; i<=n; i++) if(DP[i]) dw++;
ll tmp = n - myturn - dfsFind(1); /// your turn -> L
ans += tmp * (n-W);
}
else{ /// ���������� �� ��
ll L = 0;
for(int i=1; i<=n; i++) if(!DProot[i]) L++;
ans += L * dfsFind2(1);
}
printf("%lld", ans%MOD);
}
Compilation message
startrek.cpp: In function 'int main()':
startrek.cpp:89:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
89 | scanf("%d %lld", &n, &k);
| ~~~~~^~~~~~~~~~~~~~~~~~~
startrek.cpp:92:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
92 | scanf("%d %d", &x, &y);
| ~~~~~^~~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
2644 KB |
Output is correct |
2 |
Incorrect |
16 ms |
2644 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
3 ms |
2668 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
2644 KB |
Output is correct |
2 |
Correct |
1 ms |
2644 KB |
Output is correct |
3 |
Correct |
2 ms |
2644 KB |
Output is correct |
4 |
Correct |
1 ms |
2644 KB |
Output is correct |
5 |
Correct |
2 ms |
2644 KB |
Output is correct |
6 |
Correct |
1 ms |
2644 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
2644 KB |
Output is correct |
2 |
Correct |
1 ms |
2644 KB |
Output is correct |
3 |
Correct |
2 ms |
2644 KB |
Output is correct |
4 |
Correct |
1 ms |
2644 KB |
Output is correct |
5 |
Correct |
2 ms |
2644 KB |
Output is correct |
6 |
Correct |
1 ms |
2644 KB |
Output is correct |
7 |
Correct |
18 ms |
2748 KB |
Output is correct |
8 |
Correct |
21 ms |
2784 KB |
Output is correct |
9 |
Correct |
14 ms |
2704 KB |
Output is correct |
10 |
Correct |
14 ms |
2644 KB |
Output is correct |
11 |
Correct |
15 ms |
2644 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
2644 KB |
Output is correct |
2 |
Correct |
1 ms |
2644 KB |
Output is correct |
3 |
Correct |
2 ms |
2644 KB |
Output is correct |
4 |
Correct |
1 ms |
2644 KB |
Output is correct |
5 |
Correct |
2 ms |
2644 KB |
Output is correct |
6 |
Correct |
1 ms |
2644 KB |
Output is correct |
7 |
Correct |
18 ms |
2748 KB |
Output is correct |
8 |
Correct |
21 ms |
2784 KB |
Output is correct |
9 |
Correct |
14 ms |
2704 KB |
Output is correct |
10 |
Correct |
14 ms |
2644 KB |
Output is correct |
11 |
Correct |
15 ms |
2644 KB |
Output is correct |
12 |
Execution timed out |
1074 ms |
12772 KB |
Time limit exceeded |
13 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
2644 KB |
Output is correct |
2 |
Correct |
1 ms |
2644 KB |
Output is correct |
3 |
Correct |
2 ms |
2644 KB |
Output is correct |
4 |
Correct |
1 ms |
2644 KB |
Output is correct |
5 |
Correct |
2 ms |
2644 KB |
Output is correct |
6 |
Correct |
1 ms |
2644 KB |
Output is correct |
7 |
Correct |
18 ms |
2748 KB |
Output is correct |
8 |
Correct |
21 ms |
2784 KB |
Output is correct |
9 |
Correct |
14 ms |
2704 KB |
Output is correct |
10 |
Correct |
14 ms |
2644 KB |
Output is correct |
11 |
Correct |
15 ms |
2644 KB |
Output is correct |
12 |
Correct |
2 ms |
2644 KB |
Output is correct |
13 |
Incorrect |
14 ms |
2644 KB |
Output isn't correct |
14 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
2644 KB |
Output is correct |
2 |
Correct |
1 ms |
2644 KB |
Output is correct |
3 |
Correct |
2 ms |
2644 KB |
Output is correct |
4 |
Correct |
1 ms |
2644 KB |
Output is correct |
5 |
Correct |
2 ms |
2644 KB |
Output is correct |
6 |
Correct |
1 ms |
2644 KB |
Output is correct |
7 |
Correct |
18 ms |
2748 KB |
Output is correct |
8 |
Correct |
21 ms |
2784 KB |
Output is correct |
9 |
Correct |
14 ms |
2704 KB |
Output is correct |
10 |
Correct |
14 ms |
2644 KB |
Output is correct |
11 |
Correct |
15 ms |
2644 KB |
Output is correct |
12 |
Execution timed out |
1074 ms |
12772 KB |
Time limit exceeded |
13 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
2644 KB |
Output is correct |
2 |
Incorrect |
16 ms |
2644 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |