Submission #646596

#	Time	Username	Problem	Language	Result	Execution time	Memory
646596		Vanilla	Arboras (RMI20_arboras)	C++17	0 / 100	221 ms	55608 KiB

arboras

#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];
multiset <int64> ms[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}]);
        ms[u].insert(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);
}

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;
    }
    int q;
    cin >> q;
    dfs(0);
    p[0] = -1;
    int64 rs = 0;
    for (int i = 0; i < n; i++){
        ms[i].insert(0);
        rs = (rs + dp[i]) % mod;
    }
    cout << rs << "\n";
    while (q--) {
        int64 x,y;
        cin >> x >> y;
        int u = x;
        while (u) {
            ms[p[u]].erase(ms[p[u]].find(*--ms[u].end() + c[{p[u], u}]));;
            rs = (rs - dp[p[u]] + mod) % mod;
            dp[p[u]] = 0;
            u = p[u];
        }
        c[{p[x], x}]+=y;
        u = x;
        while (u) {
            ms[p[u]].insert(*--ms[u].end() + c[{p[u], u}]);
            if (ms[p[u]].size() >= 1) dp[p[u]] += *--ms[p[u]].end();
            if (ms[p[u]].size() >= 2) dp[p[u]] += *----ms[p[u]].end();
            rs = (rs + dp[p[u]] + mod) % mod;
            u = p[u];
        }
        cout << rs << "\n";
    }
    return 0;
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 13
• Subtask 3: 0 / 31
• Subtask 4: 0 / 45