#include <bits/stdc++.h>
using namespace std;
typedef long long int64;
const int64 mod = 1e9 + 7;
const int maxn = 1e5 + 2;
int64 dp[maxn], down[maxn];
map <pair <int, int>, int64> c;
int p[maxn];
vector <int> ad [maxn];
int n;
void upd (int u) {
vector <int64> d;
down[u] = 0;
dp[u] = 0;
for (int v: ad[u]) {
down[u] = max(down[u], down[v] + c[{u,v}]);
d.push_back(down[v] + c[{u,v}]);
}
sort(d.rbegin(), d.rend());
for (int i = 0; i < min((int) d.size(), 2); i++) dp[u]+=d[i];
}
void dfs (int u) {
for (int v: ad[u]) {
dfs(v);
}
upd(u);
}
int64 calc () {
for (int i = 0; i < n; i++) dp[i] = 0;
dfs(0);
int64 rs = 0;
for (int i = 0; i < n; i++){
rs+=dp[i];
}
return rs % mod;
}
int main() {
cin >> n;
for (int i = 1; i <= n - 1; i++){
int x;
cin >> x;
ad[x].push_back(i);
p[i] = x;
}
for (int i = 1; i <= n - 1; i++){
int x;
cin >> x;
c[{p[i], i}] = x;
}
if (n <= 1000) {
cout << calc() << "\n";
int q;
cin >> q;
while (q--) {
int64 x,y;
cin >> x >> y;
c[{p[x], x}] += y;
cout << calc() << "\n";
}
}
else {
dfs(0);
p[0] = -1;
int64 rs = 0;
for (int i = 0; i < n; i++){
rs = (rs + dp[i]) % mod;
}
cout << rs << "\n";
int q;
cin >> q;
while (q--) {
int64 x,y;
cin >> x >> y;
c[{p[x], x}]+=y;
x = p[x];
while (x != -1) {
// cout << q << " " << x << " " << dp[x] << "\n";
rs = (rs - dp[x] + mod) % mod;
upd(x);
rs = (rs + dp[x] + mod) % mod;
x = p[x];
}
cout << rs << "\n";
}
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
160 ms |
2772 KB |
Output is correct |
2 |
Correct |
145 ms |
2772 KB |
Output is correct |
3 |
Correct |
145 ms |
2748 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1658 ms |
13464 KB |
Output is correct |
2 |
Execution timed out |
5053 ms |
14144 KB |
Time limit exceeded |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Execution timed out |
5055 ms |
13416 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
160 ms |
2772 KB |
Output is correct |
2 |
Correct |
145 ms |
2772 KB |
Output is correct |
3 |
Correct |
145 ms |
2748 KB |
Output is correct |
4 |
Correct |
1658 ms |
13464 KB |
Output is correct |
5 |
Execution timed out |
5053 ms |
14144 KB |
Time limit exceeded |
6 |
Halted |
0 ms |
0 KB |
- |