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 |
---|---|---|---|---|---|---|---|---|---|
#213610 | #2715. 8.4t4 | huangyuhe | 0 | 10ms | 1624kb | C++11 | 754b | 2024-11-12 21:41:09 | 2024-11-12 23:56:31 |
answer
#include <bits/stdc++.h>
#define C__ const
#define int long long
using namespace std;
C__ int N_ = 5010, MOD = 1e9 + 7;
int n, a[N_], b[N_];
vector<int> g[N_];
void dfs(int u, int p) {
a[u] = 1;
for (int v : g[u]) if (v != p) {
dfs(v, u);
(a[u] *= b[v]) %= MOD;
(b[u] += b[v]) %= MOD;
}
(b[u] += a[u]) %= MOD;
}
void change(int u, int p) {
for (int v : g[u]) if (v != p) {
(a[v] *= ((b[u] - b[v]) % MOD + MOD) % MOD) %= MOD;
change(v, u);
}
}
signed main() {
cin >> n;
for (int i = 1; i < n; i++) {
int u, v;
cin >> u >> v;
g[u].push_back(v);
g[v].push_back(u);
}
dfs(1, 0);
change(1, 0);
int ans = 0;
for (int i = 1; i <= n; i++) (ans += a[i]) %= MOD;
cout << ans << "\n";
return 0;
}
详细
小提示:点击横条可展开更详细的信息
Test #1:
score: 0
Wrong Answer
time: 0ms
memory: 1368kb
input:
10 1 2 1 3 3 4 3 5 3 6 3 7 1 8 5 9 5 10
output:
114
result:
wrong answer 1st numbers differ - expected: '227506.00000', found: '114.00000', error = '0.99950'
Test #2:
score: 0
Wrong Answer
time: 0ms
memory: 1368kb
input:
10 1 2 1 3 3 4 4 5 5 6 4 7 5 8 8 9 8 10
output:
712
result:
wrong answer 1st numbers differ - expected: '70140.00000', found: '712.00000', error = '0.98985'
Test #3:
score: 0
Wrong Answer
time: 0ms
memory: 1372kb
input:
100 1 2 1 3 1 4 3 5 5 6 4 7 7 8 8 9 8 10 3 11 7 12 1 13 5 14 8 15 10 16 7 17 1 18 6 19 10 20 15 21 7...
output:
285118581
result:
wrong answer 1st numbers differ - expected: '875072841.00000', found: '285118581.00000', error = '0....
Test #4:
score: 0
Wrong Answer
time: 0ms
memory: 1368kb
input:
100 1 2 2 3 3 4 4 5 4 6 6 7 5 8 8 9 8 10 1 11 6 12 4 13 9 14 13 15 7 16 3 17 15 18 17 19 9 20 8 21 4...
output:
437523147
result:
wrong answer 1st numbers differ - expected: '706867541.00000', found: '437523147.00000', error = '0....
Test #5:
score: 0
Wrong Answer
time: 0ms
memory: 1372kb
input:
100 1 2 2 3 3 4 2 5 2 6 5 7 2 8 4 9 7 10 5 11 11 12 6 13 8 14 13 15 5 16 11 17 16 18 11 19 7 20 19 2...
output:
5689489
result:
wrong answer 1st numbers differ - expected: '515055734.00000', found: '5689489.00000', error = '0.98...
Test #6:
score: 0
Wrong Answer
time: 0ms
memory: 1392kb
input:
500 1 2 1 3 3 4 3 5 5 6 1 7 3 8 8 9 4 10 6 11 7 12 2 13 11 14 8 15 7 16 9 17 2 18 3 19 15 20 2 21 20...
output:
886548347
result:
wrong answer 1st numbers differ - expected: '28964814.00000', found: '886548347.00000', error = '29....
Test #7:
score: 0
Wrong Answer
time: 0ms
memory: 1396kb
input:
500 1 2 1 3 1 4 2 5 5 6 5 7 4 8 8 9 1 10 4 11 8 12 6 13 13 14 13 15 12 16 1 17 10 18 13 19 1 20 1 21...
output:
336784187
result:
wrong answer 1st numbers differ - expected: '900482908.00000', found: '336784187.00000', error = '0....
Test #8:
score: 0
Wrong Answer
time: 3ms
memory: 1624kb
input:
5000 1 2 1 3 1 4 3 5 3 6 5 7 4 8 4 9 1 10 5 11 6 12 10 13 12 14 14 15 12 16 8 17 14 18 9 19 8 20 20 ...
output:
9716686
result:
wrong answer 1st numbers differ - expected: '255910011.00000', found: '9716686.00000', error = '0.96...
Test #9:
score: 0
Wrong Answer
time: 4ms
memory: 1624kb
input:
5000 1 2 1 3 1 4 2 5 1 6 5 7 2 8 5 9 4 10 9 11 10 12 8 13 7 14 13 15 12 16 5 17 9 18 8 19 3 20 4 21 ...
output:
196789325
result:
wrong answer 1st numbers differ - expected: '506490313.00000', found: '196789325.00000', error = '0....
Test #10:
score: 0
Wrong Answer
time: 3ms
memory: 1624kb
input:
5000 1 2 1 3 1 4 4 5 4 6 3 7 2 8 8 9 6 10 9 11 3 12 3 13 7 14 13 15 4 16 10 17 9 18 10 19 5 20 17 21...
output:
970625436
result:
wrong answer 1st numbers differ - expected: '738067707.00000', found: '970625436.00000', error = '0....