4127. Abs

https://hydro.ac/d/bzoj/record/62e375b3a0c462a1ac98fdfa

BZOJ/4127/4127.cpp

@@ -0,0 +1,260 @@
+#include <iostream>
+#include <limits>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e5 + 5;
+
+int n, m, a[N];
+std::vector<int> g[N];
+int cnt, id[N], rid[N], fa[N], dep[N], top[N], son[N], siz[N];
+
+struct node {
+    int l, r;
+    long long sum, max, d;
+    size_t size;
+
+    node()
+        : l(0),
+          r(0),
+          sum(0),
+          max(std::numeric_limits<long long>::min()),
+          d(0),
+          size(0) {}
+
+    node(int _l, int _r)
+        : l(_l),
+          r(_r),
+          sum(0),
+          max(std::numeric_limits<long long>::min()),
+          d(0),
+          size(0) {}
+} tr1[N << 2], tr2[N << 2];  // tr1: 正数  tr2: 负数
+
+void dfs1(int u, int f) {
+    fa[u] = f;
+    dep[u] = dep[f] + 1;
+    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;
+    rid[id[u]] = u;
+    top[u] = t;
+
+    if (!son[u]) return;
+    dfs2(son[u], t);
+
+    for (int v : g[u]) {
+        if (v == fa[u] || v == son[u]) continue;
+        dfs2(v, v);
+    }
+}
+
+inline void pushup(node* tr, int u) {
+    tr[u].sum = tr[u << 1].sum + tr[u << 1 | 1].sum;
+    tr[u].max = std::max(tr[u << 1].max, tr[u << 1 | 1].max);
+    tr[u].size = tr[u << 1].size + tr[u << 1 | 1].size;
+}
+
+inline void pushdown(node* tr, int u) {
+    if (tr[u].d) {
+        tr[u << 1].sum += tr[u].d * tr[u << 1].size;
+        if (tr[u << 1].size) tr[u << 1].max += tr[u].d;
+        tr[u << 1].d += tr[u].d;
+
+        tr[u << 1 | 1].sum += tr[u].d * tr[u << 1 | 1].size;
+        if (tr[u << 1 | 1].size) tr[u << 1 | 1].max += tr[u].d;
+        tr[u << 1 | 1].d += tr[u].d;
+
+        tr[u].d = 0;
+    }
+}
+
+void build(int u, int l, int r) {
+    tr1[u] = node(l, r);
+    tr2[u] = node(l, r);
+
+    if (l == r) {
+        if (a[rid[l]] >= 0) {
+            tr1[u].sum = a[rid[l]];
+            tr1[u].max = a[rid[l]];
+            tr1[u].size = 1;
+
+        } else {
+            tr2[u].sum = a[rid[l]];
+            tr2[u].max = a[rid[l]];
+            tr2[u].size = 1;
+        }
+
+        return;
+    }
+
+    int mid = l + r >> 1;
+
+    build(u << 1, l, mid);
+    build(u << 1 | 1, mid + 1, r);
+
+    pushup(tr1, u);
+    pushup(tr2, u);
+}
+
+long long query_sum(int u, int l, int r) {
+    if (l <= tr1[u].l && tr1[u].r <= r) {
+        return tr1[u].sum - tr2[u].sum;
+    }
+
+    int mid = tr1[u].l + tr1[u].r >> 1;
+    long long res = 0;
+
+    pushdown(tr1, u);
+    pushdown(tr2, u);
+
+    if (l <= mid) res += query_sum(u << 1, l, r);
+    if (r > mid) res += query_sum(u << 1 | 1, l, r);
+
+    return res;
+}
+
+long long query_max(node* tr, int u, int l, int r) {
+    if (l <= tr[u].l && tr[u].r <= r) {
+        return tr[u].max;
+    }
+
+    int mid = tr[u].l + tr[u].r >> 1;
+    long long res = std::numeric_limits<long long>::min();
+
+    pushdown(tr1, u);
+    pushdown(tr2, u);
+
+    if (l <= mid) res = std::max(res, query_max(tr, u << 1, l, r));
+    if (r > mid) res = std::max(res, query_max(tr, u << 1 | 1, l, r));
+
+    return res;
+}
+
+void swap_max(int u, int l, int r) {
+    if (tr2[u].max <= 0) return;
+
+    if (tr2[u].l == tr2[u].r) {
+        tr1[u] = tr2[u];
+        tr2[u] = node(l, r);
+
+        return;
+    }
+
+    int mid = tr1[u].l + tr1[u].r >> 1;
+
+    pushdown(tr1, u);
+    pushdown(tr2, u);
+
+    if (l <= mid) swap_max(u << 1, l, r);
+    if (r > mid) swap_max(u << 1 | 1, l, r);
+
+    pushup(tr1, u);
+    pushup(tr2, u);
+}
+
+void modify(int u, int l, int r, int d) {
+    if (l <= tr1[u].l && tr1[u].r <= r) {
+        tr1[u].sum += d * tr1[u].size;
+        tr1[u].d += d;
+        if (tr1[u].size) tr1[u].max += d;
+
+        tr2[u].sum += d * tr2[u].size;
+        tr2[u].d += d;
+        if (tr2[u].size) tr2[u].max += d;
+
+        return;
+    }
+
+    int mid = tr1[u].l + tr1[u].r >> 1;
+
+    pushdown(tr1, u);
+    pushdown(tr2, u);
+
+    if (l <= mid) modify(u << 1, l, r, d);
+    if (r > mid) modify(u << 1 | 1, l, r, d);
+
+    pushup(tr1, u);
+    pushup(tr2, u);
+}
+
+void modify_path(int u, int v, int d) {
+    while (top[u] != top[v]) {
+        if (dep[top[u]] < dep[top[v]]) std::swap(u, v);
+        modify(1, id[top[u]], id[u], d);
+        swap_max(1, id[top[u]], id[u]);
+        u = fa[top[u]];
+    }
+
+    if (dep[u] < dep[v]) std::swap(u, v);
+    modify(1, id[v], id[u], d);
+    swap_max(1, id[v], id[u]);
+}
+
+long long query_path(int u, int v) {
+    long long res = 0;
+
+    while (top[u] != top[v]) {
+        if (dep[top[u]] < dep[top[v]]) std::swap(u, v);
+        res += query_sum(1, id[top[u]], id[u]);
+        u = fa[top[u]];
+    }
+
+    if (dep[u] < dep[v]) std::swap(u, v);
+    res += query_sum(1, id[v], id[u]);
+
+    return res;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> m;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+    }
+
+    for (int i = 1, u, v; i < n; i++) {
+        cin >> u >> v;
+
+        g[u].emplace_back(v);
+        g[v].emplace_back(u);
+    }
+
+    dfs1(1, 0);
+    dfs2(1, 1);
+
+    build(1, 1, n);
+
+    while (m--) {
+        int op, u, v;
+
+        cin >> op >> u >> v;
+
+        if (op == 1) {
+            int d;
+
+            cin >> d;
+
+            modify_path(u, v, d);
+        } else {  // op == 2
+            cout << query_path(u, v) << endl;
+        }
+    }
+
+    return 0;
+}