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  1. /* AUTHOR: TUAN ANH - BUI */
  2. // ~~ icebear ~~
  3. #include <bits/stdc++.h>
  4. using namespace std;
  5.  
  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. int node[N << 2], lazy[N << 2];
  44.  
  45. void pushDown(int id, int l, int r) {
  46.     int mid = (l + r) >> 1;
  47.     if (lazy[id]) {
  48.         node[id << 1] += (mid - l + 1) * lazy[id];
  49.         node[id << 1 | 1] += (r - mid) * lazy[id];
  50.         lazy[id << 1] += lazy[id];
  51.         lazy[id << 1 | 1] += lazy[id];
  52.         lazy[id] = 0;
  53.     }
  54. }
  55.  
  56. void update(int id, int l, int r, int u, int v, int k) {
  57.     if (l > v || r < u || u > v) return;
  58.     if (u <= l && r <= v) {
  59.         node[id] += (r - l + 1) * k;
  60.         lazy[id] += k;
  61.         return;
  62.     }
  63.  
  64.     pushDown(id, l, r);
  65.     int mid = (l + r) >> 1;
  66.     update(id << 1, l, mid, u, v, k);
  67.     update(id << 1 | 1, mid + 1, r, u, v, k);
  68.     node[id] = node[id << 1] + node[id << 1 | 1];
  69. }
  70.  
  71. int get(int id, int l, int r, int u, int v) {
  72.     if (l > v || r < u || u > v) return 0;
  73.     if (u <= l && r <= v) return node[id];
  74.     pushDown(id, l, r);
  75.     int mid = (l + r) >> 1;
  76.     return get(id << 1, l, mid, u, v) + get(id << 1 | 1, mid + 1, r, u, v);
  77. }
  78.  
  79. void dfs(int u) {
  80.     sz[u] = 1;
  81.     for(int v : G[u]) if (v != par[u]) {
  82.         par[v] = u;
  83.         h[v] = h[u] + 1;
  84.         dfs(v);
  85.         sz[u] += sz[v];
  86.     }
  87. }
  88.  
  89. void hld(int u) {
  90.     if (chainHead[cur_chain] == 0) {
  91.         chainHead[cur_chain] = u;
  92.     }
  93.     idChain[u] = cur_chain;
  94.     pos[u] = ++cur_pos;
  95.     tour[cur_pos] = u;
  96.  
  97.     int hvy = 0;
  98.     for(int v : G[u]) if (v != par[u] && sz[v] > sz[hvy])
  99.         hvy = v;
  100.  
  101.     if (hvy > 0) hld(hvy);
  102.  
  103.     for(int v : G[u]) if (v != par[u] && v != hvy) {
  104.         cur_chain++;
  105.         hld(v);
  106.     }
  107. }
  108.  
  109. int LCA(int u, int v) {
  110.     while(idChain[u] != idChain[v]) {
  111.         if (idChain[u] < idChain[v]) swap(u, v);
  112.         u = par[chainHead[idChain[u]]];
  113.     }
  114.     return (h[u] < h[v] ? u : v);
  115. }
  116.  
  117. void updatePath(int u, int v) {
  118.     int p = LCA(u, v);
  119.     while(idChain[u] != idChain[p]) {
  120.         update(1, 1, n, pos[chainHead[idChain[u]]], pos[u], +1);
  121.         u = par[chainHead[idChain[u]]];
  122.     }
  123.     while(idChain[v] != idChain[p]) {
  124.         update(1, 1, n, pos[chainHead[idChain[v]]], pos[v], +1);
  125.         v = par[chainHead[idChain[v]]];
  126.     }
  127.     if (h[u] > h[v]) swap(u, v);
  128.     update(1, 1, n, pos[u] + 1, pos[v], +1); // ko update w[u]
  129. }
  130.  
  131. int getPath(int u, int v) {
  132.     int ans = 0;
  133.    int p = LCA(u, v);
  134.     while(idChain[u] != idChain[p]) {
  135.         ans += get(1, 1, n, pos[chainHead[idChain[u]]], pos[u]);
  136.         u = par[chainHead[idChain[u]]];
  137.     }
  138.     while(idChain[v] != idChain[p]) {
  139.         ans += get(1, 1, n, pos[chainHead[idChain[v]]], pos[v]);
  140.         v = par[chainHead[idChain[v]]];
  141.     }
  142.     if (h[u] > h[v]) swap(u, v);
  143.     ans += get(1, 1, n, pos[u] + 1, pos[v]); // ko get w[u]
  144.     return ans;
  145. }
  146.  
  147. void init(void) {
  148.     cin >> n >> q;
  149.     FOR(i, 2, n) {
  150.         int u, v;
  151.         cin >> u >> v;
  152.         G[u].pb(v);
  153.         G[v].pb(u);
  154.     }
  155. }
  156.  
  157. void process(void) {
  158.     dfs(1);
  159.     hld(1);
  160.     while(q--) {
  161.         char t; cin >> t;
  162.         int u, v; cin >> u >> v;
  163.         if (t == 'P') {
  164.             updatePath(u, v);
  165.         } else cout << getPath(u, v) << '\n';
  166.     }
  167. }
  168.  
  169. int main() {
  170.     ios_base::sync_with_stdio(0);
  171.     cin.tie(0); cout.tie(0);
  172.     if (fopen(task".inp", "r")) {
  173.         freopen(task".inp", "r", stdin);
  174.         freopen(task".out", "w", stdout);
  175.     }
  176.     int tc = 1;
  177. //    cin >> tc;
  178.     while(tc--) {
  179.         init();
  180.         process();
  181.     }
  182.     return 0;
  183. }
  184.  
  185.  
Success #stdin #stdout 0.01s 13716KB
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https://ideone.com/q7Xdpp
language:
C++14 (gcc 8.3)
created:
3 hours ago
visibility:
public

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