Submission #619055

#	Time	Username	Problem	Language	Result	Execution time	Memory
619055		Je_O	Dynamic Diameter (CEOI19_diameter)	C++17	31 / 100	5038 ms	8764 KiB

diameter

// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC target("avx2")
#include<bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;

const int N = 1e5 + 5;
const int LOG = 18;
const int INF = 1e9;
vector<iii> vec;
vector<ii> lst[N];
int dist[N];

void solve_sub2(int n, int q, int w){
    int last = 0;
    while(q--){
        int d, e; cin >> d >> e;
        d = (d + last) % (n - 1);
        e = (e + last) % w;
        vec[d].fi = e;
        for(int i = 1; i <= n; ++i)lst[i].clear();
        for(int i = 0; i < n - 1; ++i){
            lst[vec[i].se.fi].pb(mp(vec[i].se.se, vec[i].fi));
            lst[vec[i].se.se].pb(mp(vec[i].se.fi, vec[i].fi));
        }
        for(int i = 1; i <= n; ++i)dist[i] = INF;
        queue<int> q;
        q.push(1);
        dist[1] = 0;
        while(!q.empty()){
            int cur = q.front(); q.pop();
            for(int i = 0; i < lst[cur].size(); ++i){
                int nx = lst[cur][i].fi;
                int cs = dist[cur] + lst[cur][i].se;
                if(cs < dist[nx]){
                    dist[nx] = cs;
                    q.push(nx);
                }
            }
        }
        ii maxdist = mp(-1, -1);
        for(int i = 1; i <= n; ++i){
            maxdist = max(maxdist, mp(dist[i], i));
        }
        for(int i = 1; i <= n; ++i)dist[i] = INF;
        q.push(maxdist.se);
        dist[maxdist.se] = 0;
        while(!q.empty()){
            int cur = q.front(); q.pop();
            for(int i = 0; i < lst[cur].size(); ++i){
                int nx = lst[cur][i].fi;
                int cs = dist[cur] + lst[cur][i].se;
                if(cs < dist[nx]){
                    dist[nx] = cs;
                    q.push(nx);
                }
            }
        }
        int ans = -1;
        for(int i = 1; i <= n; ++i){
            ans = max(ans, dist[i]);
        }
        last = ans;
        cout << ans << '\n';
    }
    return;
}

map<int, int> mep;

void solve_sub3(int n, int q, int w){
    int last = 0;
    while(q--){
        int d, e; cin >> d >> e;
        d = (d + last) % (n - 1);
        e = (e + last) % w;
        --mep[vec[d].fi];
        if(mep[vec[d].fi] == 0)mep.erase(vec[d].fi);
        ++mep[e];
        vec[d].fi = e;
        auto it = mep.end();
        --it;
        int ans = it->fi;
        if(it->se > 1)ans += it->fi;
        else{
            --it;
            ans += it->fi;
        }
        last = ans;
        cout << ans << '\n';
    }
    return;
}

int par[N];
int depth[N];
int cost[N];
int ar[LOG][N];
int lf[N], rg[N];

struct node{
    int mx1, mx2, lz;
};

node st[LOG][4 * N];

node merge(node a, node b){
    return {max(a.mx1, b.mx1), max(min(a.mx1, b.mx1), max(a.mx2, b.mx2)), 0};
}

void build(int idx, int l, int r, int lg){
    if(l == r){
        st[lg][l] = {ar[lg][l], -1, 0};
        return;
    }
    int m = (l + r)/2;
    build(idx * 2, l, m, lg);
    build(idx * 2 + 1, m + 1, r, lg);
    st[lg][idx] = merge(st[lg][idx * 2], st[lg][idx * 2 + 1]);
    return;
}

void apply(int idx, int l, int r, int v, int lg){
    st[lg][idx].mx1 += v;
    st[lg][idx].mx2 += v;
    st[lg][idx].lz += v;
    return;
}

void pushdown(int idx, int l, int r, int lg){
    if(st[lg][idx].lz == 0)return;
    int m = (l + r)/2;
    apply(idx * 2, l, m, st[lg][idx].lz, lg);
    apply(idx * 2 + 1, m + 1, r, st[lg][idx].lz, lg);
    st[lg][idx].lz = 0;
    return;
}

void upd(int idx, int l, int r, int x, int y, int v, int lg){
    if(l > y || r < x)return;
    if(l >= x && r <= y){
        apply(idx, l, r, v, lg);
        return;
    }
    pushdown(idx, l, r, lg);
    int m = (l + r)/2;
    upd(idx * 2, l, m, x, y, v, lg);
    upd(idx * 2 + 1, m + 1, r, x, y, v, lg);
    st[lg][idx] = merge(st[lg][idx * 2], st[lg][idx * 2 + 1]);
    return;
}

node get(int idx, int l, int r, int x, int y, int lg){
    if(l > y || r < x)return {-1, -1, 0};
    if(l >= x && r <= y)return st[idx][lg];
    pushdown(idx, l, r, lg);
    int m = (l + r)/2;
    return merge(get(idx * 2, l, m, x, y, lg), get(idx * 2 + 1, m + 1, r, x, y, lg));
}

ii dfs(int idx, int p){
    par[idx] = p;
    ii res = mp(INF, 0);
    for(int i = 0; i < lst[idx].size(); ++i){
        int nx = lst[idx][i].fi;
        if(nx == p)continue;
        cost[nx] = lst[idx][i].se;
        depth[nx] = depth[idx] + 1;
        ii cur = dfs(nx, idx);
        res.fi = min(res.fi, cur.fi);
        res.se = max(res.se, cur.se);
    }
    lf[idx] = res.fi; rg[idx] = res.se;
    return res;
}

void build_ar(int l, int r){
    for(int i = l; i <= r; ++i){
        int idx = i;
        int sum_cost = 0;
        while(par[idx] != -1){
            sum_cost += cost[idx];
            idx = par[idx];
            ar[depth[idx]][i] = sum_cost;
        }
    }
    return;
}

int main(){
    ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
    int n, q, w; cin >> n >> q >> w;
    bool sub3 = true;
    for(int i = 0; i < n - 1; ++i){
        int a, b, c; cin >> a >> b >> c;
        lst[a].pb(mp(b, c));
        lst[b].pb(mp(a, c));
        vec.pb(mp(c, mp(a, b)));
        ++mep[c];
        if(a != 1 && b != 1)sub3 = false;
    }
    if(n <= 5000 && q <= 5000){
        solve_sub2(n, q, w);
        return 0;
    }
    if(sub3){
        solve_sub3(n, q, w);
        return 0;
    }
    mep.clear();
    dfs(1, -1);
    int id_l = 0;
    for(int i = 1; i <= n; ++i){
        if(lst[i].size() == 1){
            id_l = i;
            break;
        }
    }
    build_ar(id_l, n);
    for(int i = 0; i < LOG; ++i)build(1, 1, n, i);
    for(int i = 1; i < id_l; ++i){
        node res = get(1, 1, n, lf[i], rg[i], depth[i]);
        mep[res.mx1 + res.mx2]++;
    }
    int last = 0;
    while(q--){
        int d, e; cin >> d >> e;
        d = (d + last) % (n - 1);
        e = (e + last) % w;
        int x = vec[d].se.fi, y = vec[d].se.se;
        if(depth[x] < depth[y])swap(x, y);
        int idx = x;
        while(par[idx] != -1){
            idx = par[idx];
            node res = get(1, 1, n, lf[idx], rg[idx], depth[idx]);
            mep[res.mx1 + res.mx2]--;
            if(mep[res.mx1 + res.mx2] == 0)mep.erase(res.mx1 + res.mx2);
            upd(1, 1, n, lf[x], rg[x], e - cost[x], depth[idx]);
            res = get(1, 1, n, lf[idx], rg[idx], depth[idx]);
            mep[res.mx1 + res.mx2]++;
        }
        cost[x] = e;
        vec[d].fi = e;
        auto it = mep.end();
        --it;
        int ans = it->fi;
        if(it->se > 1){
            ans += it->fi;
        }else{
            --it;
            ans += it->fi;
        }
        last = ans;
        cout << ans << '\n';
    }
    return 0;
}

Compilation message (stderr)

diameter.cpp: In function 'void solve_sub2(int, int, int)':
diameter.cpp:39:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |             for(int i = 0; i < lst[cur].size(); ++i){
      |                            ~~^~~~~~~~~~~~~~~~~
diameter.cpp:57:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |             for(int i = 0; i < lst[cur].size(); ++i){
      |                            ~~^~~~~~~~~~~~~~~~~
diameter.cpp: In function 'ii dfs(int, int)':
diameter.cpp:171:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  171 |     for(int i = 0; i < lst[idx].size(); ++i){
      |                    ~~^~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 13 / 13
• Subtask 3: 7 / 7
• Subtask 4: 0 / 18
• Subtask 5: 0 / 24
• Subtask 6: 0 / 27