Submission #1101142

#	Time	Username	Problem	Language	Result	Execution time	Memory
1101142		Neco_arc	Dynamic Diameter (CEOI19_diameter)	C++17	100 / 100	276 ms	53624 KiB

diameter

#include <bits/stdc++.h>

#define ll long long
#define ull unsigned long long
#define all(x) x.begin(), x.end()
#define Neco "Dynamic Diameter"
#define resp(x) sort(all(x)), x.resize(unique(all(x)) - x.begin())
#define getbit(x,i) ((x >> i)&1)
#define _left id * 2, l, mid
#define _right id * 2 + 1, mid + 1, r
#define cntbit(x) __builtin_popcountll(x)
#define fi(i, a, b) for(int i = a; i <= b; i++)
#define fid(i, a, b) for(int i = a; i >= b; i--)
#define maxn (int) 2e5 + 7

using namespace std;

const ll mod = 1e9 + 7; //972663749
const ll base = 911382323;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll GetRandom(ll l, ll r) {
    return uniform_int_distribution<ll> (l, r)(rng);
}

int n, q, Time; ll W;
int rn[maxn], In[maxn], Out[maxn]; ll w[maxn];
struct dl { int u, v; ll w; } E[maxn];
vector<int> edges[maxn];

void dfs_tour(int u, int par) {
    rn[++Time] = u, In[u] = Time;
    for(int v : edges[u]) if(v != par) {
        dfs_tour(v, u); rn[++Time] = u;
    }
    Out[u] = Time;
}

struct IT {
    ll store[4 * maxn];
    struct Node {
        ll Diameter, MaxH, MinH, MaxPref, MaxSuff;
        void Add(ll w) {
            MaxH += w, MinH += w;
            MaxPref -= w, MaxSuff -= w;
        }
    } st[4 * maxn];

    Node cb(const Node x, const Node y) {
        Node ans;
        ans.MaxH = max(x.MaxH, y.MaxH), ans.MinH = min(x.MinH, y.MinH);

        ans.MaxPref = max({x.MaxPref, y.MaxPref, x.MaxH - 2 * y.MinH});
        ans.MaxSuff = max({x.MaxSuff, y.MaxSuff, y.MaxH - 2 * x.MinH});

        ans.Diameter = max(x.Diameter, y.Diameter);
        ans.Diameter = max(ans.Diameter, x.MaxPref + y.MaxH);
        ans.Diameter = max(ans.Diameter, y.MaxSuff + x.MaxH);

        return ans;
    }

    void down(int id) {
        ll val = store[id];
        fi(i, 0, 1) {
            st[id * 2 + i].Add(val), store[id * 2 + i] += val;
        }
        store[id] = 0;
    }

    void update(int u, int v, ll val, int id = 1, int l = 1, int r = Time) {
        if(l > v || r < u) return;
        if(u <= l && r <= v) {
            st[id].Add(val), store[id] += val;
            return;
        }

        down(id);
        int mid = (l + r) >> 1;
        update(u, v, val, _left), update(u, v, val, _right);

        st[id] = cb(st[id * 2], st[id * 2 + 1]);
    }

    ll get() {
        return st[1].Diameter;
    }
} St;

void solve()
{

    cin >> n >> q >> W;
    fi(i, 1, n - 1) {
        int x, y; ll w; cin >> x >> y >> w;
        E[i] = {x, y, w};
        edges[x].push_back(y), edges[y].push_back(x);
    }

    dfs_tour(1, 0);
    fi(i, 1, n - 1) {
        if(In[E[i].u] > In[E[i].v]) swap(E[i].u, E[i].v);
        w[E[i].v] = E[i].w;
        St.update(In[E[i].v], Out[E[i].v], E[i].w);
    }

    ll ans = 0;
    fi(i, 1, q) {
        ll id, val; cin >> id >> val;
        id = (id + ans) % (n - 1) + 1;
        val = (val + ans) % W;

        int v = E[id].v;
        val = val - w[v], w[v] += val;

        St.update(In[v], Out[v], val);
        ans = St.get(); cout << ans << '\n';
    }


}


int main()
{

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    if(fopen(Neco".inp", "r")) {
        freopen(Neco".inp", "r", stdin);
        freopen(Neco".out", "w", stdout);
    }

    int nTest = 1;
//    cin >> nTest;

    while(nTest--)
    {
        solve();
    }


    return 0;
}

Compilation message (stderr)

diameter.cpp: In function 'int main()':
diameter.cpp:132:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  132 |         freopen(Neco".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
diameter.cpp:133:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  133 |         freopen(Neco".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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