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Submission #837786

# Submission time Handle Problem Language Result Execution time Memory
837786 2023-08-25T17:06:47 Z jasmin Dynamic Diameter (CEOI19_diameter) C++17
11 / 100
 5000 ms 269492 KB 
#include<bits/stdc++.h>
using namespace std;
#define int long long

const int INF=LLONG_MAX;
const int L=25;

struct segtree{ //lazy maximum segtree with add updates

    vector<int> tree;
    vector<int> lazy;

    segtree(int n){
        tree.assign(n*4, 0);
        lazy.assign(n*4, 0);
    }

    int update_node(int v, int add){
        tree[v] += add;
        lazy[v] += add;

        return tree[v];
    }

    void propagate(int l, int r, int v){
        if(lazy[v]==0) return;

        update_node(v*2+1, lazy[v]);
        update_node(v*2+2, lazy[v]);
        lazy[v]=0;
    }

    int update(int l, int r, int v, int ql, int qr, int add){
        if(qr<=l || r<=ql) return tree[v];
        if(ql<=l && r<=qr){
            return update_node(v, add);
        }
        propagate(l, r, v);
        int m=l+(r-l)/2;
        return tree[v] = max(update(l, m, v*2+1, ql, qr, add), update(m, r, v*2+2, ql, qr, add));
    }

    int query(int l, int r, int v, int ql, int qr){
        if(qr<=l || r<=ql) return 0;
        if(ql<=l && r<=qr){
            return tree[v];
        }
        int m=l+(r-l)/2;
        return max(query(l, m, v*2+1, ql, qr), query(m, r, v*2+2, ql, qr));
    }
};

struct segtree2{
    vector<int> tree;

    void init(int n){
        tree.assign(n*4, 0);
    }

    int update(int l, int r, int v, int x, int val){
        if(x<l || r<=x) return tree[v];
        if(l+1==r){
            return tree[v]=val;
        }
        int m=l+(r-l)/2;
        return tree[v] = max(update(l, m, v*2+1, x, val), update(m, r, v*2+2, x, val));
    }

    int query(){
        return tree[0];
    }
};

struct tree{
    int n;
    vector<pair<int,int> > edge;
    vector<vector<pair<int,int> > >adi;

    segtree2 segans;

    vector<int> level;
    vector<int> pc; //parent centroid

    vector<int> subtreesize;

    vector<int> curind;
    vector<set<pair<int, int> > >children;
    vector<set<pair<int, int> > >paths;

    vector<vector<int> > preind;
    vector<vector<int> > ssize;
    vector<vector<int> > paredge;
    vector<segtree> seg;

    tree(int ninput){
        n = ninput;
        edge.assign(n-1, {-1, -1});
        adi.assign(n, {});

        segans.init(n);

        level.assign(n, INF);
        pc.assign(n, -1);

        subtreesize.assign(n, 0);

        curind.assign(L, 0);
        children.assign(n, {});
        paths.assign(n, {});

        preind.assign(L, vector<int>(n, 0));
        ssize.assign(L, vector<int> (n, 0));
        paredge.assign(L, vector<int> (n, 0));
        seg.assign(L, segtree(n));
    }

    //centroids
    int dfs(int v, int p, int lev){ //precomputes the subtreesizes
 
        subtreesize[v] = 1;
        for(auto [u, d]: adi[v]){
            if(u==p || level[u]<lev) continue;

            subtreesize[v] += dfs(u, v, lev);
        }

        return subtreesize[v];
    }

    int centroiddfs(int v, int lev, int size){ //finds a centroid in a connected graph

        for(auto [u, d]: adi[v]){
            if(level[u] < lev) continue;

            if(subtreesize[u] > size/2){

                subtreesize[v] = size - subtreesize[u];
                return centroiddfs(u, lev, size);
            }
        }

        return v;
    }

    void find_centroids(int v, int lev, int centroidp){ //finds all centroids recursively
        int size = dfs(v, -1, lev);

        int centroid = centroiddfs(v, lev, size);
        level[centroid] = lev;
        pc[centroid]= centroidp;

        //compute all values for this component
        distancedfs(centroid, -1, 0, lev);
        
        for(auto [u, d]: adi[centroid]){
            if(level[u] < lev) continue;

            children[centroid].insert({preind[lev][u], u});
            int p = seg[lev].query(0, n, 0, preind[lev][u], preind[lev][u] + ssize[lev][u]);
            paths[centroid].insert({p, u});
        }
        paths[centroid].insert({0, -1});
        paths[centroid].insert({0, -2});

        int diameter = (*prev(paths[centroid].end())).first;
        diameter += (*prev(prev(paths[centroid].end()))).first;
    
        segans.update(0, n, 0, centroid, diameter);

        //find next centroids
        for(auto [u, d]: adi[centroid]){
            if(level[u] < lev) continue;

            find_centroids(u, lev+1, centroid);
        }
    }

    int distancedfs(int v, int p, int dist, int lev){

        preind[lev][v] = curind[lev];
        curind[lev] ++;

        seg[lev].update(0, n, 0, preind[lev][v], preind[lev][v]+1, dist);

        int s=1;
        for(auto [u, d]: adi[v]){
            if(u==p || level[u] < lev) continue;

            paredge[lev][u] = d;
            s += distancedfs(u, v, dist+d, lev);
        }

        ssize[lev][v] = s;
        return s;
    }


    int update_edge(int a, int b, int val){

        int c; int lev;
        if(level[a] > level[b]){

            c=a;    
            lev = level[a];
        }
        else{

            c=b;
            lev = level[b];
        }
        c = pc[c];
        lev--;

        for(; lev>=0; lev--){

            if(preind[lev][b]<preind[lev][a]){ 

                swap(a, b);
            } //=> a is an ancestor of b


            // update c
            int x = (*prev(children[c].upper_bound({preind[lev][b], b}))).second;
            int oldp = seg[lev].query(0, n, 0, preind[lev][x], preind[lev][x]+ssize[lev][x]);
            paths[c].erase({oldp, x});

            int add = val- paredge[lev][b];
            paredge[lev][b] = val;
            seg[lev].update(0, n, 0, preind[lev][b], preind[lev][b]+ssize[lev][b], add);

            int newp = seg[lev].query(0, n, 0, preind[lev][x], preind[lev][x] + ssize[lev][x]);
            paths[c].insert({newp, x});


            int diameterc = (*prev(paths[c].end())).first;
            diameterc += (*prev(prev(paths[c].end()))).first;
            
            segans.update(0, n, 0, c, diameterc);

            c = pc[c];
        }

        return segans.query();
    }
};

int solve(int n, vector<int>& v, vector<int>& u, vector<int>& w){
    tree g(n);

    for(int i=0; i<n-1; i++){
        int a=v[i];
        int b=u[i];
        int c=w[i];

        g.edge[i]={a, b};
        g.adi[a].push_back({b, c});
        g.adi[b].push_back({a, c});
    }

    g.find_centroids(0, 0, -1);

    int ans=g.segans.query();
    return ans;
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    int n, q, maxw;
    cin >> n >> q >> maxw;

    vector<int> v(n-1);
    vector<int> u(n-1);
    vector<int> w(n-1);
    for(int i=0; i<n-1; i++){
        cin >> v[i] >> u[i] >> w[i];
        v[i]--;
        u[i]--;
    }

    int last=0;
    for(int i=0; i<q; i++){

        int di, wi;
        cin >> di >> wi;

        int d = (di + last) % (n-1);
        int weight = (wi + last) % maxw;

        w[d] = weight;

        int ans= solve(n, v, u, w);
        cout << ans << "\n";
        last = ans;
    }

    /*tree g(n);

    for(int i=0; i<n-1; i++){
        int a, b, c;
        cin >> a >> b >> c;
        a--; b--;

        g.edge[i]={a, b};
        g.adi[a].push_back({b, c});
        g.adi[b].push_back({a, c});
    }

    g.find_centroids(0, 0, -1);

    int last=0;
    for(int i=0; i<q; i++){

        int di, wi;
        cin >> di >> wi;

        int d = (di + last) % (n-1);
        int w = (wi + last) % maxw;

        auto [a, b] = g.edge[d];


        int ans=g.update_edge(a, b, w);
        cout << ans << "\n";
        
        last = ans;
    }*/
}

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 320 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 5 ms 444 KB Output is correct
8 Correct 5 ms 468 KB Output is correct
9 Correct 5 ms 340 KB Output is correct
10 Correct 5 ms 460 KB Output is correct
11 Correct 5 ms 468 KB Output is correct
12 Correct 6 ms 444 KB Output is correct
13 Correct 9 ms 580 KB Output is correct
14 Correct 9 ms 596 KB Output is correct
15 Correct 10 ms 596 KB Output is correct
16 Correct 10 ms 596 KB Output is correct
17 Correct 10 ms 576 KB Output is correct
18 Correct 11 ms 600 KB Output is correct

Subtask #2
0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 320 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 5 ms 444 KB Output is correct
8 Correct 5 ms 468 KB Output is correct
9 Correct 5 ms 340 KB Output is correct
10 Correct 5 ms 460 KB Output is correct
11 Correct 5 ms 468 KB Output is correct
12 Correct 6 ms 444 KB Output is correct
13 Correct 9 ms 580 KB Output is correct
14 Correct 9 ms 596 KB Output is correct
15 Correct 10 ms 596 KB Output is correct
16 Correct 10 ms 596 KB Output is correct
17 Correct 10 ms 576 KB Output is correct
18 Correct 11 ms 600 KB Output is correct
19 Execution timed out 5020 ms 3176 KB Time limit exceeded
20 Halted 0 ms 0 KB -

Subtask #3
0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 4 ms 384 KB Output is correct
3 Correct 31 ms 404 KB Output is correct
4 Correct 311 ms 556 KB Output is correct
5 Correct 1502 ms 1560 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 9 ms 1620 KB Output is correct
8 Correct 82 ms 1648 KB Output is correct
9 Correct 754 ms 1672 KB Output is correct
10 Execution timed out 5039 ms 1992 KB Time limit exceeded
11 Halted 0 ms 0 KB -

Subtask #4
0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 1695 ms 3232 KB Output is correct
2 Execution timed out 5056 ms 3320 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #5
0 / 24.0

# Verdict Execution time Memory Grader output
1 Execution timed out 5067 ms 269492 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #6
0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 320 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 5 ms 444 KB Output is correct
8 Correct 5 ms 468 KB Output is correct
9 Correct 5 ms 340 KB Output is correct
10 Correct 5 ms 460 KB Output is correct
11 Correct 5 ms 468 KB Output is correct
12 Correct 6 ms 444 KB Output is correct
13 Correct 9 ms 580 KB Output is correct
14 Correct 9 ms 596 KB Output is correct
15 Correct 10 ms 596 KB Output is correct
16 Correct 10 ms 596 KB Output is correct
17 Correct 10 ms 576 KB Output is correct
18 Correct 11 ms 600 KB Output is correct
19 Execution timed out 5020 ms 3176 KB Time limit exceeded
20 Halted 0 ms 0 KB -