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  1. /* AUTHOR: TUAN ANH - BUI */
  2. // ~~ icebear ~~
  3. #include <bits/stdc++.h>
  4. using namespace std;
  5. #define int long long
  6. typedef long long ll;
  7. typedef pair<int, int> ii;
  8. typedef pair<int, ii> iii;
  9.  
  10. template<class X, class Y>
  11.     bool minimize(X &x, const Y &y) {
  12.         if (x > y) return x = y, true;
  13.         return false;
  14.     }
  15.  
  16. template<class X, class Y>
  17.     bool maximize(X &x, const Y &y) {
  18.         if (x < y) return x = y, true;
  19.         return false;
  20.     }
  21.  
  22. #define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
  23. #define FORR(i,a,b) for(int i=(a); i>=(b); --i)
  24. #define REP(i, n) for(int i=0; i<(n); ++i)
  25. #define RED(i, n) for(int i=(n)-1; i>=0; --i)
  26. #define MASK(i) (1LL << (i))
  27. #define BIT(S, i) (((S) >> (i)) & 1)
  28. #define mp make_pair
  29. #define pb push_back
  30. #define fi first
  31. #define se second
  32. #define all(x) x.begin(), x.end()
  33. #define task "icebear"
  34. /*END OF TEMPLATE. ICEBEAR AND THE CAT WILL WIN VOI26 */
  35.  
  36. const int MOD = 1e9 + 7;
  37. const int inf = (int)1e9 + 27092008;
  38. const ll INF  = (ll)1e18 + 27092008;
  39. const int N = 2e5 + 5;
  40. int n, q;
  41. vector<int> G[N];
  42. int chainHead[N], idChain[N], pos[N], tour[N], sz[N], h[N], cur_chain = 1, cur_pos = 0, par[N];
  43.  
  44. struct Node {
  45.     int best, sum, pref, suff, lazy;
  46.     friend Node combine(const Node &L, const Node &R) {
  47.         Node res;
  48.         res.best = max({L.best, R.best, L.suff + R.pref});
  49.         res.pref = max(L.pref, L.sum + R.pref);
  50.         res.suff = max(R.suff, R.sum + L.suff);
  51.         res.sum = L.sum + R.sum;
  52.         res.lazy = inf;
  53.         return res;
  54.     }
  55. } node[N << 2];
  56.  
  57. void Assign(int id, int l, int r, int k) { // gan k cho node[id]
  58.     node[id].sum = (r - l + 1) * k;
  59.     node[id].best = node[id].pref = node[id].suff = max(0LL, node[id].sum); // neu k > 0 thi lay toan bo la toi uu, con k < 0 thi ko lay gi la toi uu
  60.     node[id].lazy = k;
  61. }
  62.  
  63. void pushDown(int id, int l, int r) {
  64.     if (node[id].lazy != inf) {
  65.         int mid = (l + r) >> 1;
  66.         Assign(id << 1, l, mid, node[id].lazy);
  67.         Assign(id << 1 | 1, mid + 1, r, node[id].lazy);
  68.         node[id].lazy = inf;
  69.     }
  70. }
  71.  
  72. void update(int id, int l, int r, int u, int v, int k) {
  73.     if (l > v || r < u || u > v) return;
  74.     if (u <= l && r <= v) {
  75.         Assign(id, l, r, k);
  76.         return;
  77.     }
  78.     pushDown(id, l, r);
  79.     int mid = (l + r) >> 1;
  80.     update(id << 1, l, mid, u, v, k);
  81.     update(id << 1 | 1, mid + 1, r, u, v, k);
  82.     node[id] = combine(node[id << 1], node[id << 1 | 1]);
  83. }
  84.  
  85. Node get(int id, int l, int r, int u, int v) {
  86.     if (l > v || r < u || u > v) return {-INF, 0, 0, 0, inf};
  87.     if (u <= l && r <= v) return node[id];
  88.     pushDown(id, l, r);
  89.     int mid = (l + r) >> 1;
  90.     return combine(get(id << 1, l, mid, u, v), get(id << 1 | 1, mid + 1, r, u, v));
  91. }
  92.  
  93. void dfs(int u) {
  94.     sz[u] = 1;
  95.     for(int v : G[u]) if (v != par[u]) {
  96.         par[v] = u;
  97.         h[v] = h[u] + 1;
  98.         dfs(v);
  99.         sz[u] += sz[v];
  100.     }
  101. }
  102.  
  103. void hld(int u) {
  104.     if (chainHead[cur_chain] == 0) {
  105.         chainHead[cur_chain] = u;
  106.     }
  107.     idChain[u] = cur_chain;
  108.     pos[u] = ++cur_pos;
  109.     tour[cur_pos] = u;
  110.  
  111.     int hvy = 0;
  112.     for(int v : G[u]) if (v != par[u] && sz[v] > sz[hvy])
  113.         hvy = v;
  114.  
  115.     if (hvy > 0) hld(hvy);
  116.  
  117.     for(int v : G[u]) if (v != par[u] && v != hvy) {
  118.         cur_chain++;
  119.         hld(v);
  120.     }
  121. }
  122.  
  123. int LCA(int u, int v) {
  124.     while(idChain[u] != idChain[v]) {
  125.         if (idChain[u] < idChain[v]) swap(u, v);
  126.         u = par[chainHead[idChain[u]]];
  127.     }
  128.     return (h[u] < h[v] ? u : v);
  129. }
  130.  
  131. void updatePath(int u, int v, int c) {
  132.     int p = LCA(u, v);
  133.     while(idChain[u] != idChain[p]) {
  134.         update(1, 1, n, pos[chainHead[idChain[u]]], pos[u], c);
  135.         u = par[chainHead[idChain[u]]];
  136.     }
  137.     while(idChain[v] != idChain[p]) {
  138.         update(1, 1, n, pos[chainHead[idChain[v]]], pos[v], c);
  139.         v = par[chainHead[idChain[v]]];
  140.     }
  141.     if (h[u] > h[v]) swap(u, v);
  142.     update(1, 1, n, pos[u], pos[v], c);
  143. }
  144.  
  145. int getPath(int u, int v) {
  146.     Node L = {-INF, 0, 0, 0, inf};
  147.     Node R = L;
  148.     int p = LCA(u, v);
  149.     while(idChain[u] != idChain[p]) {
  150.         Node cur = get(1, 1, n, pos[chainHead[idChain[u]]], pos[u]);
  151.         swap(cur.pref, cur.suff);
  152.         L = combine(L, cur);
  153.         u = par[chainHead[idChain[u]]];
  154.     }
  155.     if (u != p) {
  156.         Node cur = get(1, 1, n, pos[p] + 1, pos[u]);
  157.         swap(cur.pref, cur.suff);
  158.         L = combine(L, cur);
  159.     }
  160.     while(idChain[v] != idChain[p]) {
  161.         R = combine(get(1, 1, n, pos[chainHead[idChain[v]]], pos[v]), R);
  162.         v = par[chainHead[idChain[v]]];
  163.     }
  164.     if (v != p) {
  165.         R = combine(get(1, 1, n, pos[p] + 1, pos[v]), R);
  166.     }
  167.     Node mid = get(1, 1, n, pos[p], pos[p]);
  168.     return combine(L, combine(mid, R)).best;
  169. }
  170.  
  171. int a[N];
  172. void build(int id, int l, int r) {
  173.     node[id].lazy = inf;
  174.     if (l == r) {
  175.         node[id].sum = a[tour[l]];
  176.         node[id].best = node[id].pref = node[id].suff = max(0LL, node[id].sum);
  177.         return;
  178.     }
  179.     int mid = (l + r) >> 1;
  180.     build(id << 1, l, mid);
  181.     build(id << 1 | 1, mid + 1, r);
  182.     node[id] = combine(node[id << 1], node[id << 1 | 1]);
  183. }
  184.  
  185. void init(void) {
  186.     cin >> n;
  187.     FOR(i, 1, n) cin >> a[i];
  188.     FOR(i, 2, n) {
  189.         int u, v;
  190.         cin >> u >> v;
  191.         G[u].pb(v);
  192.         G[v].pb(u);
  193.     }
  194. }
  195.  
  196. void process(void) {
  197.     dfs(1);
  198.     hld(1);
  199.     build(1, 1, n);
  200.     cin >> q;
  201.     while(q--) {
  202.         int t; cin >> t;
  203.         int u, v; cin >> u >> v;
  204.         if (t == 2) {
  205.             int c; cin >> c;
  206.             updatePath(u, v, c);
  207.         } else cout << getPath(u, v) << '\n';
  208.     }
  209. }
  210.  
  211. signed main() {
  212.     ios_base::sync_with_stdio(0);
  213.     cin.tie(0); cout.tie(0);
  214.     if (fopen(task".inp", "r")) {
  215.         freopen(task".inp", "r", stdin);
  216.         freopen(task".out", "w", stdout);
  217.     }
  218.     int tc = 1;
  219. //    cin >> tc;
  220.     while(tc--) {
  221.         init();
  222.         process();
  223.     }
  224.     return 0;
  225. }
  226.  
  227.  
Success #stdin #stdout 0.01s 5308KB
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https://ideone.com/uSZU21
language:
C++14 (gcc 8.3)
created:
1 hour ago
visibility:
public

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