Submission #1348653

#TimeUsernameProblemLanguageResultExecution timeMemory
1348653MisterReaperCats or Dogs (JOI18_catdog)C++20
100 / 100
471 ms23980 KiB
#include "bits/stdc++.h"
#include "catdog.h"

using i64 = long long;

#ifdef DEBUG 
    #include "/home/ahmetalp/Desktop/Workplace/debug.h"
#else
    #define debug(...) void(23)
#endif

constexpr int inf = int(1E9);

using M = std::array<std::array<i64, 2>, 2>;

M operator+ (const M& lhs, const M& rhs) {
    M res;
    for (int i = 0; i < 2; ++i) {
        for (int j = 0; j < 2; ++j) {
            res[i][j] = std::min({lhs[i][0] + rhs[0][j],
                                 lhs[i][0] + rhs[1][j] + 1,
                                 lhs[i][1] + rhs[0][j] + 1,
                                 lhs[i][1] + rhs[1][j]});
        }
    }
    return res;
}

#define def int mid = (l + r) >> 1, lv = v + 1, rv = v + ((mid - l) << 1)
struct segtree {
    int n;
    std::vector<M> tree;
    void init(int n_) {
        n = n_;
        tree.resize(n << 1);
        auto dfs = [&](auto&& self, int v, int l, int r) -> void {
            if (l + 1 == r) {
                tree[v] = {0, inf, inf, 0};
                debug(v, tree[v]);
                return;
            }
            def;
            self(self, lv, l, mid);
            self(self, rv, mid, r);
            tree[v] = tree[lv] + tree[rv];
        };
        dfs(dfs, 0, 0, n);
    }
    void add(int v, int l, int r, int p, int k, i64 x) {
        if (l + 1 == r) {
            debug(l, v, x);
            tree[v][k >> 1][k & 1] += x;
            return;
        }
        def;
        if (p < mid) {
            add(lv, l, mid, p, k, x);
        } else {
            add(rv, mid, r, p, k, x);
        }
        tree[v] = tree[lv] + tree[rv];
    }
    void add(int p, int k, i64 x) {
        add(0, 0, n, p, k, x);
    }
    int cnt_x = 0;
    M get(int v, int l, int r, int ql, int qr) {
        if (ql == l && r == qr) {
            cnt_x += 1;
            return tree[v];
        }
        def;
        if (qr <= mid) {
            return get(lv, l, mid, ql, qr);
        } else if (mid <= ql) {
            return get(rv, mid, r, ql, qr);
        } else {
            return get(lv, l, mid, ql, mid)
                 + get(rv, mid, r, mid, qr);
        }
    }
    M get(int l, int r) {
        cnt_x = 0;
        M res = get(0, 0, n, l, r);
        assert(cnt_x <= 50);
        return res;
    }
} seg;

constexpr int max_N = int(1E5);

int N;
std::vector<int> adj[max_N];

int tim = 0;
int siz[max_N];
int par[max_N];
int top[max_N];
int tin[max_N];
int tout[max_N];
int len[max_N];
int typ[max_N];

void dfs1(int v) {
    siz[v] = 1;
    for (auto& u : adj[v]) {
        adj[u].erase(std::find(adj[u].begin(), adj[u].end(), v));
        par[u] = v;
        dfs1(u);
        siz[v] += siz[u];
        if (siz[u] > siz[adj[v][0]]) {
            std::swap(u, adj[v][0]);
        }
    }
}

void dfs2(int v) {
    tin[v] = tim++;
    for (auto u : adj[v]) {
        if (u == adj[v][0]) {
            top[u] = top[v];
            len[top[v]] += 1;
        } else {
            top[u] = u;
            len[u] = 1;
        }
        dfs2(u);
    }
    tout[v] = tim;
}

void debug_tree() {
    // auto dfs = [&](auto&& self, int v, int l, int r) -> void {
    //     if (l + 1 == r) {
    //         debug(l, r, seg.tree[v]);
    //         return;
    //     }
    //     def;
    //     self(self, lv, l, mid);
    //     self(self, rv, mid, r);
    // };
    // dfs(dfs, 0, 0, N);
    // debug();
}

void initialize(int N, std::vector<int> A, std::vector<int> B) {
    ::N = N;
    seg.init(N);
    for (int i = 0; i < N - 1; ++i) {
        --A[i], --B[i];
        adj[A[i]].emplace_back(B[i]);
        adj[B[i]].emplace_back(A[i]);
    }
    dfs1(0);
    len[0] = 1;
    dfs2(0);
    debug(tin);
    debug(len);
    // debug_tree();
    debug();
}

void rem(int u) {
    std::vector<int> stk;
    while (top[u]) {
        u = top[u];
        stk.emplace_back(u);
        u = par[u];
    }
    std::reverse(stk.begin(), stk.end());
    for (auto v : stk) {
        M x = seg.get(tin[v], tin[v] + len[v]);
        M y {};
        seg.add(tin[par[v]], 0, -std::min({x[0][0], x[0][1], x[1][0] + 1, x[1][1] + 1}));
        seg.add(tin[par[v]], 3, -std::min({x[1][0], x[1][1], x[0][0] + 1, x[0][1] + 1}));
    }
}

void add(int u) {
    std::vector<int> stk;
    while (top[u]) {
        u = top[u];
        stk.emplace_back(u);
        u = par[u];
    }
    for (auto v : stk) {
        M x = seg.get(tin[v], tin[v] + len[v]);
        M y {};
        seg.add(tin[par[v]], 0, std::min({x[0][0], x[0][1], x[1][0] + 1, x[1][1] + 1}));
        seg.add(tin[par[v]], 3, std::min({x[1][0], x[1][1], x[0][0] + 1, x[0][1] + 1}));
    }
}

int answer() {
    debug_tree();
    M x = seg.get(0, len[0]);
    i64 res = inf;
    for (int i = 0; i < 2; ++i) {
        for (int j = 0; j < 2; ++j) {
            res = std::min(res, x[i][j]);
        }
    }
    return res;
}

int cat(int v) {
    --v;
    rem(v);
    typ[v] = 1;
    seg.add(tin[v], 3, inf);
    add(v);
    return answer();
}

int dog(int v) {
    --v;
    rem(v);
    typ[v] = 2;
    seg.add(tin[v], 0, inf);
    add(v);
    return answer();
}

int neighbor(int v) {
    --v;
    rem(v);
    if (typ[v] == 1) {
        seg.add(tin[v], 3, -inf);
    } else {
        seg.add(tin[v], 0, -inf);
    }
    typ[v] = 0;
    add(v);
    return answer();
}
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