Submission #1082334

#	Time	Username	Problem	Language	Result	Execution time	Memory
1082334		cpptowin	Dynamic Diameter (CEOI19_diameter)	C++17	31 / 100	5066 ms	392712 KiB

diameter

#include <bits/stdc++.h>
#define fo(i, d, c) for (int i = d; i <= c; i++)
#define fod(i, c, d) for (int i = c; i >= d; i--)
#define maxn 100010
#define N 1010
#define fi first
#define se second
#define pb emplace_back
#define en cout << "\n";
#define ll long long
#define inf (ll)1e18
#define bitcount(x) __builtin_popcountll(x)
#define pii pair<int, int>
#define vii vector<pii>
#define lb(x) x & -x
#define bit(i, j) ((i >> j) & 1)
#define offbit(i, j) (i ^ (1LL << j))
#define onbit(i, j) (i | (1LL << j))
#define vi vector<int>
#define all(x) x.begin(), x.end()
#define ss(x) (int)x.size()
template <typename T1, typename T2>
bool minimize(T1 &a, T2 b)
{
    if (a > b)
    {
        a = b;
        return true;
    }
    return false;
}
template <typename T1, typename T2>
bool maximize(T1 &a, T2 b)
{
    if (a < b)
    {
        a = b;
        return true;
    }
    return false;
}
using namespace std;
static struct FastInput
{
    static constexpr int BUF_SIZE = 1 << 20;
    char buf[BUF_SIZE];
    size_t chars_read = 0;
    size_t buf_pos = 0;
    FILE *in = stdin;
    char cur = 0;

    inline char get_char()
    {
        if (buf_pos >= chars_read)
        {
            chars_read = fread(buf, 1, BUF_SIZE, in);
            buf_pos = 0;
            buf[0] = (chars_read == 0 ? -1 : buf[0]);
        }
        return cur = buf[buf_pos++];
    }

    inline void tie(int) {}

    inline explicit operator bool()
    {
        return cur != -1;
    }

    inline static bool is_blank(char c)
    {
        return c <= ' ';
    }

    inline bool skip_blanks()
    {
        while (is_blank(cur) && cur != -1)
        {
            get_char();
        }
        return cur != -1;
    }

    inline FastInput &operator>>(char &c)
    {
        skip_blanks();
        c = cur;
        return *this;
    }

    inline FastInput &operator>>(string &s)
    {
        if (skip_blanks())
        {
            s.clear();
            do
            {
                s += cur;
            } while (!is_blank(get_char()));
        }
        return *this;
    }

    template <typename T>
    inline FastInput &read_integer(T &n)
    {
        // unsafe, doesn't check that characters are actually digits
        n = 0;
        if (skip_blanks())
        {
            int sign = +1;
            if (cur == '-')
            {
                sign = -1;
                get_char();
            }
            do
            {
                n += n + (n << 3) + cur - '0';
            } while (!is_blank(get_char()));
            n *= sign;
        }
        return *this;
    }

    template <typename T>
    inline typename enable_if<is_integral<T>::value, FastInput &>::type operator>>(T &n)
    {
        return read_integer(n);
    }

#if !defined(_WIN32) || defined(_WIN64)
    inline FastInput &operator>>(__int128 &n)
    {
        return read_integer(n);
    }
#endif

    template <typename T>
    inline typename enable_if<is_floating_point<T>::value, FastInput &>::type operator>>(T &n)
    {
        // not sure if really fast, for compatibility only
        n = 0;
        if (skip_blanks())
        {
            string s;
            (*this) >> s;
            sscanf(s.c_str(), "%lf", &n);
        }
        return *this;
    }
} fast_input;

#define cin fast_input

static struct FastOutput
{
    static constexpr int BUF_SIZE = 1 << 20;
    char buf[BUF_SIZE];
    size_t buf_pos = 0;
    static constexpr int TMP_SIZE = 1 << 20;
    char tmp[TMP_SIZE];
    FILE *out = stdout;

    inline void put_char(char c)
    {
        buf[buf_pos++] = c;
        if (buf_pos == BUF_SIZE)
        {
            fwrite(buf, 1, buf_pos, out);
            buf_pos = 0;
        }
    }

    ~FastOutput()
    {
        fwrite(buf, 1, buf_pos, out);
    }

    inline FastOutput &operator<<(char c)
    {
        put_char(c);
        return *this;
    }

    inline FastOutput &operator<<(const char *s)
    {
        while (*s)
        {
            put_char(*s++);
        }
        return *this;
    }

    inline FastOutput &operator<<(const string &s)
    {
        for (int i = 0; i < (int)s.size(); i++)
        {
            put_char(s[i]);
        }
        return *this;
    }

    template <typename T>
    inline char *integer_to_string(T n)
    {
        // beware of TMP_SIZE
        char *p = tmp + TMP_SIZE - 1;
        if (n == 0)
        {
            *--p = '0';
        }
        else
        {
            bool is_negative = false;
            if (n < 0)
            {
                is_negative = true;
                n = -n;
            }
            while (n > 0)
            {
                *--p = (char)('0' + n % 10);
                n /= 10;
            }
            if (is_negative)
            {
                *--p = '-';
            }
        }
        return p;
    }

    template <typename T>
    inline typename enable_if<is_integral<T>::value, char *>::type stringify(T n)
    {
        return integer_to_string(n);
    }

#if !defined(_WIN32) || defined(_WIN64)
    inline char *stringify(__int128 n)
    {
        return integer_to_string(n);
    }
#endif

    template <typename T>
    inline typename enable_if<is_floating_point<T>::value, char *>::type stringify(T n)
    {
        sprintf(tmp, "%.17f", n);
        return tmp;
    }

    template <typename T>
    inline FastOutput &operator<<(const T &n)
    {
        auto p = stringify(n);
        for (; *p != 0; p++)
        {
            put_char(*p);
        }
        return *this;
    }
} fast_output;

#define cout fast_output
const int nsqrt = 450;
const int mod = 1e9 + 7;
void add(int &x, int k)
{
    x += k;
    x %= mod;
    if (x < 0)
        x += mod;
}
void del(int &x, int k)
{
    x -= k;
    x %= mod;
    if (x < 0)
        x += mod;
}
struct SegmentTree
{
    vector<pair<ll, int>> st;
    vector<ll> lazy;
    int n;
    vector<ll> a;
    /// real n
    SegmentTree(int _n = 0) : n(_n)
    {
        st.resize(4 * n + 10);
        lazy.resize(4 * n + 10);
    }
    void resize(int _n)
    {
        n = _n;
        st.resize(4 * n + 10);
        lazy.resize(4 * n + 10);
    }
    void down(int id, int l, int r)
    {
        st[id << 1].fi += lazy[id];
        lazy[id << 1] += lazy[id];
        st[id << 1 | 1].fi += lazy[id];
        lazy[id << 1 | 1] += lazy[id];
        lazy[id] = 0;
    }
    void build(int id, int l, int r)
    {
        if (l == r)
        {
            st[id] = {a[l - 1], l};
            return;
        }
        int mid = l + r >> 1;
        build(id << 1, l, mid);
        build(id << 1 | 1, mid + 1, r);
        st[id] = max(st[id << 1], st[id << 1 | 1]);
    }
    void build(vector<ll> vv)
    {
        a = vv;
        resize(ss(vv));
        build(1, 1, n);
    }
    void update(int id, int l, int r, int u, int v, int val)
    {
        if (u > r || l > v)
            return;
        if (u <= l && r <= v)
        {
            st[id].fi += val;
            lazy[id] += val;
            return;
        }
        down(id, l, r);
        int mid = (l + r) >> 1;
        update(id << 1, l, mid, u, v, val);
        update(id << 1 | 1, mid + 1, r, u, v, val);
        st[id] = max(st[id << 1], st[id << 1 | 1]);
    }

    pair<ll, int> get(int id, int l, int r, int u, int v)
    {
        if (l > v || u > r)
            return {-inf, 0};
        if (u <= l && r <= v)
            return st[id];
        down(id, l, r);
        int mid = (l + r) >> 1;
        return max(get(id << 1, l, mid, u, v), get(id << 1 | 1, mid + 1, r, u, v));
    }
    pair<ll, int> get(int l, int r)
    {
        return get(1, 1, n, l, r);
    }
    void update(int l, int r, int val)
    {
        update(1, 1, n, l, r, val);
    }
    pair<ll, int> getall()
    {
        return get(1, 1, n, 1, n);
    }
};
SegmentTree st[maxn];
int n, q;
ll lim;
vector<pair<ll, ll>> ke[maxn];
int cnt;
unordered_map<int, int> topo[maxn];
unordered_map<int, bool> child[maxn];
unordered_map<int, int> rt[maxn];
map<int, pii> euler[maxn];
// centroid decomposition
bool is_remove[maxn];
int sz[maxn];
int dfs_size(int u, int parent = -1)
{
    sz[u] = 1;
    for (auto [v, w] : ke[u])
    {
        if (v == parent or is_remove[v])
            continue;
        sz[u] += dfs_size(v, u);
    }
    return sz[u];
}
int dfs_centroid(int u, int tree_size, int parent = 0)
{
    for (auto [v, w] : ke[u])
    {
        if (v == parent or is_remove[v])
            continue;
        if (2 * sz[v] > tree_size)
            return dfs_centroid(v, tree_size, u);
    }
    return u;
}
vector<ll> vv;
void dfs_dist(int u, int par, int centroid, int root, ll dist)
{
    int pos = ++cnt;
    child[centroid][u] = 1;
    rt[centroid][u] = root;
    topo[centroid][pos] = u;
    if (ss(ke[u]) == 1)
        vv.pb(dist);
    else
        vv.pb(-inf);
    for (auto [v, w] : ke[u])
        if (v != par and !is_remove[v])
            dfs_dist(v, u, centroid, root, dist + w);
    int tail = cnt;
    euler[centroid][u] = {pos, tail};
}
vi child_cen[maxn];
void build_centroid(int u, int par = 0)
{
    u = dfs_centroid(u, dfs_size(u));
    is_remove[u] = 1;
    cnt = 1;
    vv.clear();
    vv.pb(-inf);
    child[u][u] = 1;
    for (auto [v, w] : ke[u])
        if (v != par and !is_remove[v])
            dfs_dist(v, u, u, v, w);
    if(ss(vv) > 1)
    child_cen[par].pb(u);
    else return;
    euler[u][u] = {1, cnt};
    st[u].build(vv);
    for (auto [v, w] : ke[u])
    {
        if (is_remove[v])
            continue;
        build_centroid(v, u);
    }
}
ll res;
void update(int u, int x, int y, ll w, ll w1)
{
    if (child[u].count(x) and child[u].count(y))
    {
        int l, r;
        if (euler[u][x].fi > euler[u][y].fi)
            l = euler[u][x].fi, r = euler[u][x].se;
        else
            l = euler[u][y].fi, r = euler[u][y].se;
        st[u].update(l, r, w1 - w);
    }
    auto [val, pos] = st[u].getall();
    pos = rt[u][topo[u][pos]];
    pair<ll, int> max2 = max(st[u].get(1, euler[u][pos].fi - 1),
                             st[u].get(euler[u][pos].se + 1, st[u].n));
    maximize(res, val + max(max2.fi, 0ll));
    for (int it : child_cen[u])
        update(it, x, y, w, w1);
}
array<ll, 3> edge[maxn];
main()
{
#define name "TASK"
    if (fopen(name ".inp", "r"))
    {
        freopen(name ".inp", "r", stdin);
        freopen(name ".out", "w", stdout);
    }
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> n >> q >> lim;
    fo(i, 1, n - 1)
    {
        ll u, v, w;
        cin >> u >> v >> w;
        ke[u].pb(v, w);
        ke[v].pb(u, w);
        edge[i] = {u, v, w};
    }
    build_centroid(1);
    ll preans = 0;
    while (q--)
    {
        int d, e;
        cin >> d >> e;
        d = (d + preans) % (n - 1);
        e = (e + preans) % lim;
        auto [u, v, w] = edge[d + 1];
        res = 0;
        for (int it : child_cen[0])
            update(it, u, v, w, e);
        preans = res;
        cout << res;
        en;
        edge[d + 1][2] = e;
    }
}

Compilation message (stderr)

diameter.cpp: In member function 'void SegmentTree::build(int, int, int)':
diameter.cpp:316:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  316 |         int mid = l + r >> 1;
      |                   ~~^~~
diameter.cpp: At global scope:
diameter.cpp:463:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  463 | main()
      | ^~~~
diameter.cpp: In function 'int main()':
diameter.cpp:472:13: warning: passing NULL to non-pointer argument 1 of 'void FastInput::tie(int)' [-Wconversion-null]
  472 |     cin.tie(NULL);
      |             ^~~~
diameter.cpp:63:21: note:   declared here
   63 |     inline void tie(int) {}
      |                     ^~~
diameter.cpp:468:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  468 |         freopen(name ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
diameter.cpp:469:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  469 |         freopen(name ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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