HDU 5029 Relief grain（离线+线段树+启发式合并）（2014 ACM/ICPC Asia Regional Guangzhou Online）

  1 #include <cstdio>
  2 #include <cstring>
  3 #include <iostream>
  4 #include <algorithm>
  5 #include <vector>
  6 using namespace std;
  7 typedef pair<int, int> PII;
  8 
  9 const int MAXV = 100010;
 10 const int MAXE = MAXV << 1;
 11 const int MAXT = MAXV << 2;
 12 
 13 int head[MAXV], ecnt;
 14 int to[MAXE], next[MAXE];
 15 int n, m, maxz;
 16 
 17 void init() {
 18     memset(head + 1, -1, n * sizeof(int));
 19     ecnt = 0;
 20 }
 21 
 22 void add_edge(int u, int v) {
 23     to[ecnt] = v; next[ecnt] = head[u]; head[u] = ecnt++;
 24     to[ecnt] = u; next[ecnt] = head[v]; head[v] = ecnt++;
 25 }
 26 
 27 #define mid ((l + r) >> 1)
 28 struct Node {
 29     Node *lson, *rson;
 30     int val, cnt, size;
 31     Node() {
 32         val = cnt = size = 0;
 33     }
 34     void update() {
 35         Node *s = lson->cnt >= rson->cnt ? lson : rson;
 36         val = s->val;
 37         cnt = s->cnt;
 38         size = lson->size + rson->size;
 39     }
 40 } *nil;
 41 Node statePool[MAXT * 3];
 42 Node *stk[MAXT * 3];
 43 int top, scnt;
 44 
 45 Node* new_node() {
 46     Node *p;
 47     if(top) p = stk[--top];
 48     else p = &statePool[scnt++];
 49     p->lson = p->rson = nil;
 50     p->val = p->cnt = p->size = 0;
 51     return p;
 52 }
 53 
 54 void del_node(Node *p) {
 55     stk[top++] = p;
 56 }
 57 
 58 void remove(Node *y) {
 59     if(y->lson != nil) remove(y->lson);
 60     if(y->rson != nil) remove(y->rson);
 61     del_node(y);
 62 }
 63 
 64 void modify(Node *&x, int l, int r, int pos, int val) {
 65     if(x == nil) x = new_node();
 66     if(l == r) {
 67         x->val = l;
 68         x->cnt += val;
 69         x->size = (x->cnt > 0);
 70     } else {
 71         if(pos <= mid) modify(x->lson, l, mid, pos, val);
 72         if(mid < pos) modify(x->rson, mid + 1, r, pos, val);
 73         x->update();
 74     }
 75 }
 76 
 77 void merge(Node *x, Node *y, int l, int r) {
 78     if(y->size != 0) {
 79         if(l == r) {
 80             modify(x, 1, maxz, l, y->cnt);
 81         } else {
 82             merge(x, y->lson, l, mid);
 83             merge(x, y->rson, mid + 1, r);
 84         }
 85     }
 86 }
 87 
 88 Node* merge(Node *x, Node *y) {
 89     if(x->size < y->size) swap(x, y);
 90     merge(x, y, 1, maxz);
 91     remove(y);
 92     return x;
 93 }
 94 
 95 vector<PII> query[MAXV];
 96 struct Modify {
 97     int u, v, c, lca;
 98     void read(int i) {
 99         scanf("%d%d%d", &u, &v, &c);
100         maxz = max(maxz, c);
101         query[u].push_back(make_pair(v, i));
102         query[v].push_back(make_pair(u, i));
103     }
104 } ask[MAXV];
105 int fa[MAXV];
106 bool vis[MAXV];
107 
108 int find_set(int x) {
109     return fa[x] == x ? x : fa[x] = find_set(fa[x]);
110 }
111 
112 void lca(int u, int f) {
113     for(int p = head[u]; ~p; p = next[p]) {
114         int &v = to[p];
115         if(v == f || vis[v]) continue;
116         lca(v, u);
117         fa[v] = u;
118     }
119     vis[u] = true;
120     for(vector<PII>::iterator it = query[u].begin(); it != query[u].end(); ++it) {
121         if(vis[it->first]) {
122             ask[it->second].lca = find_set(it->first);
123         }
124     }
125 }
126 
127 vector<PII> pre[MAXV], nxt[MAXV];
128 int ans[MAXV];
129 
130 Node* dfs(int u, int f) {
131     Node *x = new_node();
132     for(int p = head[u]; ~p; p = next[p]) {
133         int v = to[p];
134         if(v == f) continue;
135         x = merge(x, dfs(v, u));
136     }
137     for(vector<PII>::iterator it = pre[u].begin(); it != pre[u].end(); ++it)
138         modify(x, 1, maxz, it->first, it->second);
139     ans[u] = x->val;
140     for(vector<PII>::iterator it = nxt[u].begin(); it != nxt[u].end(); ++it)
141         modify(x, 1, maxz, it->first, it->second);
142     return x;
143 }
144 
145 void solve() {
146     for(int i = 1; i <= n; ++i) {
147         fa[i] = i;
148         vis[i] = false;
149         pre[i].clear(); nxt[i].clear();
150     }
151     lca(1, 0);
152     for(int i = 0; i < m; ++i) {
153         const Modify &t = ask[i];
154         pre[t.u].push_back(make_pair(t.c, 1));
155         pre[t.v].push_back(make_pair(t.c, 1));
156         pre[t.lca].push_back(make_pair(t.c, -1));
157         nxt[t.lca].push_back(make_pair(t.c, -1));
158     }
159     top = scnt = 0;
160     Node *p = dfs(1, 0);
161     if(p != nil) remove(p);
162 
163     for(int i = 1; i <= n; ++i)
164         printf("%d\n", ans[i]);
165 }
166 
167 int main() {
168     nil = new Node();
169     nil->lson = nil->rson = nil;
170 
171     while(scanf("%d%d", &n, &m) != EOF) {
172         if(n == 0 && m == 0) break;
173         init();
174         for(int i = 1, u, v; i < n; ++i) {
175             scanf("%d%d", &u, &v);
176             add_edge(u, v);
177         }
178         for(int i = 1; i <= n; ++i) query[i].clear();
179         maxz = 0;
180         for(int i = 0; i < m; ++i) ask[i].read(i);
181         solve();
182     }
183 }