#include<bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC target("fma,sse,sse2,sse3,avx")
#pragma GCC optimize("unroll-loops")
typedef long long ll;
typedef pair<int, int> pii;
const int MAX = 2e6 + 15;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
#define pb push_back
#define sz(x) (int) x.size()
#define fr first
#define sc second
#define mp make_pair
#define all(x) x.begin(), x.end()
#define dbg(x) cout << #x << ": " << "[ " << x << " ]\n"
ll n, q, p[MAX], wg[MAX], dp[MAX][2], use[MAX][2], ans;
vector<int> adj[MAX], weight[MAX];
void dfs(int u){
for(int i = 0; i < sz(adj[u]); i++){
int v = adj[u][i], w = weight[u][i];
dfs(v);
if(dp[v][0] + w > dp[u][0]){
dp[u][1] = dp[u][0];
dp[u][0] = dp[v][0] + w;
use[u][1] = use[u][0];
use[u][0] = v;
}else if(dp[v][0] + w > dp[u][1]){
dp[u][1] = dp[v][0] + w;
use[u][1] = v;
}
}
ans += dp[u][0] + dp[u][1]; ans %= MOD;
}
void update(int u, int x){ //Update the tree and answer
wg[u] += x;
while(u != 0){
if(use[p[u]][0] == u){
ans += dp[u][0] + wg[u] - dp[p[u]][0];
dp[p[u]][0] = dp[u][0] + wg[u];
}else if(dp[u][0] + wg[u] > dp[p[u]][0]){
ans += dp[p[u]][0] - dp[p[u]][1] + dp[u][0] + wg[u] - dp[p[u]][0];
dp[p[u]][1] = dp[p[u]][0];
use[p[u]][1] = use[p[u]][0];
dp[p[u]][0] = dp[u][0] + wg[u];
use[p[u]][0] = u;
}else if(dp[u][0] + wg[u] > dp[p[u]][1]){
ans += dp[u][0] + wg[u] - dp[p[u]][1];
dp[p[u]][1] = dp[u][0] + wg[u];
use[p[u]][1] = u;
}
ans %= MOD;
u = p[u];
}
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n;
for(int i = 1; i < n; i++){
cin >> p[i];
adj[p[i]].pb(i);
}
for(int i = 1; i < n; i++){
cin >> wg[i];
weight[p[i]].pb(wg[i]);
}
dfs(0);
cout << ans << '\n';
cin >> q;
while(q--){
int u, add; cin >> u >> add;
update(u, add);
cout << ans << '\n';
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
45 ms |
94408 KB |
Output is correct |
2 |
Correct |
46 ms |
94412 KB |
Output is correct |
3 |
Correct |
45 ms |
94284 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
121 ms |
103656 KB |
Output is correct |
2 |
Correct |
99 ms |
97796 KB |
Output is correct |
3 |
Correct |
95 ms |
98280 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3999 ms |
106116 KB |
Output is correct |
2 |
Execution timed out |
5026 ms |
106672 KB |
Time limit exceeded |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
45 ms |
94408 KB |
Output is correct |
2 |
Correct |
46 ms |
94412 KB |
Output is correct |
3 |
Correct |
45 ms |
94284 KB |
Output is correct |
4 |
Correct |
121 ms |
103656 KB |
Output is correct |
5 |
Correct |
99 ms |
97796 KB |
Output is correct |
6 |
Correct |
95 ms |
98280 KB |
Output is correct |
7 |
Correct |
3999 ms |
106116 KB |
Output is correct |
8 |
Execution timed out |
5026 ms |
106672 KB |
Time limit exceeded |
9 |
Halted |
0 ms |
0 KB |
- |