Submission #948007

# Submission time Handle Problem Language Result Execution time Memory
948007 2024-03-17T12:18:28 Z huutuan Arboras (RMI20_arboras) C++14
100 / 100
317 ms 50516 KB
#include<bits/stdc++.h>

using namespace std;

#define int long long

const int mod=1e9+7;

struct FenwickTree{
   int n;
   vector<int> t;
   void init(int _n){
      n=_n;
      t.assign(n+1, 0);
   }
   void update(int pos, int val){
      for (int i=pos; i<=n; i+=i&(-i)) t[i]+=val;
   }
   void update(int l, int r, int val){
      update(l, val);
      if (r<n) update(r+1, -val);
   }
   int get(int pos){
      int ans=0;
      for (int i=pos; i; i-=i&(-i)) ans+=t[i];
      return ans;
   }
} bit;

struct Node{
   pair<int, int> val, lazy;
   Node (pair<int, int> _val={0, 0}){
      val=_val;
      lazy={0, 0};
   }
   Node operator+(const Node &b){
      return Node({(val.first+b.val.first)%mod, val.second});
   }
};

struct SegmentTree{
   int n;
   vector<Node> t;
   void init(int _n){
      n=_n;
      t.assign(4*n+1, Node());
   }
   void apply(int k, int l, int r, pair<int, int> val){
      if (l!=r) t[k].val.first=(t[k].val.first+(r-l+1)*(val.first%mod))%mod;
      else t[k].val.first=(t[k].val.first+(r-l+1)*val.first);
      t[k].val.second=val.second;
      t[k].lazy.first=(t[k].lazy.first+val.first);
      t[k].lazy.second=val.second;
   }
   void push(int k, int l, int r){
      if (t[k].lazy.second){
         int mid=(l+r)>>1;
         apply(k<<1, l, mid, t[k].lazy);
         apply(k<<1|1, mid+1, r, t[k].lazy);
         t[k].lazy={0, 0};
      }
   }
   void update(int k, int l, int r, int L, int R, pair<int, int> val){
      if (r<L || R<l) return;
      if (L<=l && r<=R){
         apply(k, l, r, val);
         return;
      }
      push(k, l, r);
      int mid=(l+r)>>1;
      update(k<<1, l, mid, L, R, val);
      update(k<<1|1, mid+1, r, L, R, val);
      t[k]=t[k<<1]+t[k<<1|1];
   }
   Node get(int k, int l, int r, int pos){
      if (l==r) return t[k];
      push(k, l, r);
      int mid=(l+r)>>1;
      if (pos<=mid) return get(k<<1, l, mid, pos);
      return get(k<<1|1, mid+1, r, pos);
   }
} st;

const int N=1e5+10, LG=17;
int n, q, par[N], dpar[N], dis[N], dep[N], up[LG][N], tin[N], tout[N], tdfs, sz[N];
pair<int, int> dist1[N], dist2[N];
int ans=0;
int head[N];
vector<int> g[N];

void dfs_sz(int u){
   sz[u]=1;
   for (int &v:g[u]){
      dfs_sz(v);
      sz[u]+=sz[v];
      if (sz[v]>sz[g[u][0]]) swap(v, g[u][0]);
   }
}

void dfs(int u, int h){
   head[u]=h;
   tin[u]=++tdfs;
   dep[u]=dep[par[u]]+1;
   for (int k=1; k<LG; ++k) up[k][u]=up[k-1][up[k-1][u]];
   pair<int, int> d1, d2;
   if (g[u].empty()) d1={0, u};
   for (int v:g[u]){
      dis[v]=dis[u]+dpar[v];
      up[0][v]=u;
      dfs(v, v==g[u][0]?h:v);
      pair<int, int> dd={dist1[v].first+dpar[v], dist1[v].second};
      if (d1<dd) d2=d1, d1=dd;
      else d2=max(d2, dd);
   }
   dist1[u]=d1; dist2[u]=d2;
   tout[u]=tdfs;
}

int lift(int u, int d){
   for (int k=0; k<LG; ++k){
      if (d>>k&1) u=up[k][u];
   }
   return u;
}

int get_dist(int u, int v){
   return bit.get(tin[v])-bit.get(tin[u]);
}

void update(int u, int v, pair<int, int> d){
   while (head[u]!=head[v]){
      if (dep[head[u]]>dep[head[v]]) swap(u, v);
      st.update(1, 1, n, tin[head[v]], tin[v], d);
      v=par[head[v]];
   }
   if (tin[u]>tin[v]) swap(u, v);
   st.update(1, 1, n, tin[u], tin[v], d);
}

int32_t main(){
   #ifdef sus
   freopen("C.inp", "r", stdin);
   freopen("C.out", "w", stdout);
   #endif
   ios_base::sync_with_stdio(false);
   cin.tie(nullptr);
   cin >> n;
   for (int i=2; i<=n; ++i) cin >> par[i], ++par[i], g[par[i]].push_back(i);
   for (int i=2; i<=n; ++i) cin >> dpar[i];
   dfs_sz(1);
   dfs(1, 1);
   st.init(n);
   bit.init(n);
   for (int i=1; i<=n; ++i){
      ans=(ans+dist1[i].first)%mod;
      ans=(ans+dist2[i].first)%mod;
      bit.update(tin[i], tin[i], dis[i]);
      st.update(1, 1, n, tin[i], tin[i], dist1[i]);
   }
   cout << ans << '\n';
   cin >> q;
   while (q--){
      int u, d; cin >> u >> d; ++u;
      bit.update(tin[u], tout[u], d);
      int w=st.get(1, 1, n, tin[u]).val.second;
      u=par[u];
      int cnt=0;
      while (u){
         auto p=st.get(1, 1, n, tin[u]).val;
         pair<int, int> tmp={get_dist(u, w), w};
         if (p>tmp){
            if (tmp>=dist2[u]){
               ans=(ans-dist2[u].first%mod+mod)%mod;
               dist2[u]=tmp;
               ans=(ans+dist2[u].first)%mod;
            }
            break;
         }
         int diff=tmp.first-p.first;
         int v=u;
         for (int k=LG-1; k>=0; --k) if (up[k][u]){
            int u2=up[k][u];
            auto p2=st.get(1, 1, n, tin[u2]).val;
            if (p2<=make_pair(get_dist(u2, w), w) && p2.second==p.second) u=u2;
         }
         ans=(ans+(dep[v]-dep[u]+1)*(diff%mod))%mod;
         ans=(ans-dist2[v].first%mod+mod)%mod;
         if (p.second!=w) dist2[v]=p;
         ans=(ans+dist2[v].first)%mod;
         update(u, v, {diff, w});
         ++cnt;
         u=par[u];
      }
      cout << ans << '\n';
   }
   return 0;
}
# Verdict Execution time Memory Grader output
1 Correct 4 ms 19288 KB Output is correct
2 Correct 4 ms 19444 KB Output is correct
3 Correct 4 ms 19292 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 227 ms 41460 KB Output is correct
2 Correct 89 ms 40404 KB Output is correct
3 Correct 148 ms 40788 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 317 ms 44268 KB Output is correct
2 Correct 188 ms 48084 KB Output is correct
3 Correct 128 ms 42320 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 4 ms 19288 KB Output is correct
2 Correct 4 ms 19444 KB Output is correct
3 Correct 4 ms 19292 KB Output is correct
4 Correct 227 ms 41460 KB Output is correct
5 Correct 89 ms 40404 KB Output is correct
6 Correct 148 ms 40788 KB Output is correct
7 Correct 317 ms 44268 KB Output is correct
8 Correct 188 ms 48084 KB Output is correct
9 Correct 128 ms 42320 KB Output is correct
10 Correct 315 ms 44200 KB Output is correct
11 Correct 186 ms 48076 KB Output is correct
12 Correct 146 ms 42324 KB Output is correct
13 Correct 302 ms 49400 KB Output is correct
14 Correct 269 ms 50516 KB Output is correct