P4211 [LNOI2014]LCA

https://www.luogu.com.cn/record/101128189

Luogu/P4211/P4211.cpp

@@ -0,0 +1,194 @@
+#include <iostream>
+#include <algorithm>
+#include <functional>
+#include <iterator>
+#include <tuple>
+#include <utility>
+#include <vector>
+
+const int N = 5e4 + 5;
+const int mod = 201314;
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+int n, q, now, ans[N];
+int cnt, id[N], fa[N], dep[N], siz[N], top[N], son[N];
+std::vector<int> g[N];
+std::vector<std::tuple<int, int, int, int>> qs;
+
+struct node {
+    int l, r, s, d;
+
+    node(const int &_l = 0, const int &_r = 0)
+        : l(_l), r(_r), s(0), d(0) {}
+} tr[N << 2];
+
+void pushup(int u) {
+    tr[u].s = tr[u << 1].s + tr[u << 1 | 1].s;
+}
+
+void pushdown(int u) {
+    if (!tr[u].d) return;
+
+    tr[u << 1].s += (tr[u << 1].r - tr[u << 1].l + 1) * tr[u].d;
+    tr[u << 1].d += tr[u].d;
+
+    tr[u << 1 | 1].s += (tr[u << 1 | 1].r - tr[u << 1 | 1].l + 1) * tr[u].d;
+    tr[u << 1 | 1].d += tr[u].d;
+
+    tr[u].d = 0;
+}
+
+void build(int u, int l, int r) {
+    tr[u] = node(l, r);
+
+    if (l == r) return;
+
+    int mid = (l + r) >> 1;
+
+    build(u << 1, l, mid);
+    build(u << 1 | 1, mid + 1, r);
+
+    pushup(u);
+}
+
+void modify(int u, int l, int r, int x) {
+    if (l <= tr[u].l && tr[u].r <= r) {
+        tr[u].s += (tr[u].r - tr[u].l + 1) * x;
+        tr[u].d += x;
+
+        return;
+    }
+
+    pushdown(u);
+
+    int mid = (tr[u].l + tr[u].r) >> 1;
+
+    if (l <= mid) modify(u << 1, l, r, x);
+    if (r > mid) modify(u << 1 | 1, l, r, x);
+
+    pushup(u);
+}
+
+int query(int u, int l, int r) {
+    if (l <= tr[u].l && tr[u].r <= r) {
+        return tr[u].s;
+    }
+
+    pushdown(u);
+
+    int mid = (tr[u].l + tr[u].r) >> 1;
+    int res = 0;
+
+    if (l <= mid) res += query(u << 1, l, r);
+    if (r > mid) res += query(u << 1 | 1, l, r);
+
+    return res;
+}
+
+void dfs1(int u, int f) {
+    dep[u] = dep[f] + 1;
+    fa[u] = f;
+    siz[u] = 1;
+
+    for (int v : g[u]) {
+        if (v == f) continue;
+
+        dfs1(v, u);
+
+        siz[u] += siz[v];
+
+        if (siz[son[u]] < siz[v]) son[u] = v;
+    }
+}
+
+void dfs2(int u, int t) {
+    id[u] = ++cnt;
+    top[u] = t;
+
+    if (son[u]) dfs2(son[u], t);
+
+    for (int v : g[u]) {
+        if (v == fa[u] || v == son[u]) continue;
+
+        dfs2(v, v);
+    }
+}
+
+void modify_path(int u, int v, int x) {
+    while (top[u] != top[v]) {
+        if (dep[top[u]] < dep[top[v]]) std::swap(u, v);
+
+        modify(1, id[top[u]], id[u], x);
+        u = fa[top[u]];
+    }
+
+    if (dep[u] < dep[v]) std::swap(u, v);
+
+    modify(1, id[v], id[u], x);
+}
+
+int query_path(int u, int v) {
+    int res = 0;
+
+    while (top[u] != top[v]) {
+        if (dep[top[u]] < dep[top[v]]) std::swap(u, v);
+
+        res += query(1, id[top[u]], id[u]);
+        u = fa[top[u]];
+    }
+
+    if (dep[u] < dep[v]) std::swap(u, v);
+
+    res += query(1, id[v], id[u]);
+
+    return res;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> q;
+
+    for (int i = 2, x; i <= n; i++) {
+        cin >> x;
+
+        x++;
+        g[i].emplace_back(x);
+        g[x].emplace_back(i);
+    }
+
+    dfs1(1, 1);
+    dfs2(1, 1);
+    build(1, 1, n);
+
+    for (int i = 1, l, r, z; i <= q; i++) {
+        cin >> l >> r >> z;
+
+        l++, r++, z++;
+
+        qs.emplace_back(i, l - 1, z, -1);
+        qs.emplace_back(i, r, z, 1);
+    }
+
+    std::sort(qs.begin(), qs.end(), [&](const decltype(qs)::value_type &lhs, const decltype(qs)::value_type &rhs) -> bool {
+        return std::get<1>(lhs) < std::get<1>(rhs);
+    });
+
+    for (auto o : qs) {
+        int id, pos, z, k;
+
+        std::tie(id, pos, z, k) = o;
+
+        while (now < pos) modify_path(1, ++now, 1);
+
+        ans[id] = ((ans[id] + k * query_path(1, z)) % mod + mod) % mod;
+    }
+
+    std::copy_n(ans + 1, q, std::ostream_iterator<int>(cout, "\n"));
+
+    return 0;
+}