【HDOJ】4358 Boring counting

基本思路是将树形结构转线性结构，因为查询的是从任意结点到叶子结点的路径。
从而将每个查询转换成区间，表示从该结点到叶子结点的路径。
离线做，按照右边界升序排序。
利用树状数组区间修改。
树状数组表示有K个数据的数量，利用pos进行维护。
假设现有的sz >= K， 那么需要对区间进行修改。

 /* 4358 */
 #include <iostream>
 #include <sstream>
 #include <string>
 #include <map>
 #include <queue>
 #include <set>
 #include <stack>
 #include <vector>
 #include <deque>
 #include <algorithm>
 #include <cstdio>
 #include <cmath>
 #include <ctime>
 #include <cstring>
 #include <climits>
 #include <cctype>
 #include <cassert>
 #include <functional>
 #include <iterator>
 #include <iomanip>
 using namespace std;
 //#pragma comment(linker,"/STACK:102400000,1024000")

 #define sti                set<int>
 #define stpii            set<pair<int, int> >
 #define mpii            map<int,int>
 #define vi                vector<int>
 #define pii                pair<int,int>
 #define vpii            vector<pair<int,int> >
 #define rep(i, a, n)     for (int i=a;i<n;++i)
 #define per(i, a, n)     for (int i=n-1;i>=a;--i)
 #define clr                clear
 #define pb                 push_back
 #define mp                 make_pair
 #define fir                first
 #define sec                second
 #define all(x)             (x).begin(),(x).end()
 #define SZ(x)             ((int)(x).size())
 #define lson            l, mid, rt<<1
 #define rson            mid+1, r, rt<<1|1

 typedef struct {
     int v, nxt;
 } edge_t;

 typedef struct node_t {
     int w, id; 

     friend bool operator< (const node_t& a, const node_t& b) {
         if (a.w == b.w)
             return a.id < b.id;
         return a.w < b.w;
     }

 } node_t;

 typedef struct ques_t {
     int l, r, id;
 } ques_t;

 const int maxn = 1e5+;
 const int maxv = maxn;
 const int maxe = maxv * ;
 int head[maxv], l;
 edge_t E[maxe];
 int Beg[maxn], End[maxn];
 int val[maxn], W[maxn];
 node_t nd[maxn];
 vi pvc[maxn];
 int dfs_clock;
 int n, K;
 int a[maxn];
 ques_t Q[maxn];
 int ans[maxn];

 bool compq (const ques_t& a, const ques_t& b) {
     if (a.r == b.r)
         return a.l < b.l;
     return a.r < b.r;
 }

 void init() {
     memset(head, -, sizeof(head));
     memset(a, , sizeof(a));
     dfs_clock = l = ;
 }

 void addEdge(int u, int v) {
     E[l].v = v;
     E[l].nxt = head[u];
     head[u] = l++;

     E[l].v = u;
     E[l].nxt = head[v];
     head[v] = l++;
 }

 void dfs(int u, int fa) {
     int v, k;

     Beg[u] = ++dfs_clock;
     val[dfs_clock] = W[u];
     for (k=head[u]; k!=-; k=E[k].nxt) {
         v = E[k].v;
         if (v == fa)
             continue;
         dfs(v, u);
     }
     End[u] = dfs_clock;
 }

 int lowest(int x) {
     return x & -x;
 }

 int sum(int x) {
     int ret = ;

     while (x) {
         ret += a[x];
         x -= lowest(x);
     }

     return ret;
 }

 void update(int x, int delta) {
     while (x <= n) {
         a[x] += delta;
         x += lowest(x);
     }
 }

 void solve() {
     int q;
     int u, v;

     sort(nd+, nd++n);
     int cnt = ;
     W[nd[].id] = cnt;
     rep(i, , n+) {
         if (nd[i].w==nd[i-].w) {
             W[nd[i].id] = cnt;
         } else {
             W[nd[i].id] = ++cnt;
         }
     }

     dfs(, );

     rep(i, , cnt+) {
         pvc[i].clr();
         pvc[i].pb();
     }

     scanf("%d", &q);
     rep(i, , q) {
         scanf("%d", &u);
         Q[i].l = Beg[u];
         Q[i].r = End[u];
         Q[i].id = i;
     }

     sort(Q, Q+q, compq);
     int sz;
     int j = ;

     rep(i, , n+) {
         pvc[val[i]].pb(i);
         sz = SZ(pvc[val[i]]) - ;
         if (sz >= K) {
             if (sz > K) {
                 update(pvc[val[i]][sz-K-]+, -);
                 update(pvc[val[i]][sz-K]+, );
             }
             update(pvc[val[i]][sz-K]+, );
             update(pvc[val[i]][sz-K+]+, -);
         }
         while (j<q && Q[j].r==i) {
             ans[Q[j].id] = sum(Q[j].l);
             ++j;
         }
     }

     rep(i, , q)
         printf("%d\n", ans[i]);
 }

 int main() {
     ios::sync_with_stdio(false);
     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
         freopen("data.out", "w", stdout);
     #endif

     int t;
     int u, v;

     scanf("%d", &t);
     rep(tt, , t+) {
         init();
         scanf("%d %d", &n, &K);
         rep(i, , n+) {
             scanf("%d", &W[i]);
             nd[i].id = i;
             nd[i].w = W[i];
         }
         rep(i, , n) {
             scanf("%d %d", &u, &v);
             addEdge(u, v);
         }
         printf("Case #%d:\n", tt);
         solve();
         if (tt != t)
             putchar('\n');
     }

     #ifndef ONLINE_JUDGE
         printf("time = %d.\n", (int)clock());
     #endif

     return ;
 }

数据发生器。

 from copy import deepcopy
 from random import randint, shuffle
 import shutil
 import string

 def GenDataIn():
     with open("data.in", "w") as fout:
         t = 10
         bound = 10**9
         fout.write("%d\n" % (t))
         for tt in xrange(t):
             n = randint(100, 200)
             K = randint(1, 5)
             fout.write("%d %d\n" % (n, K))
             ust = [1]
             vst = range(2, n+1)
             L = []
             for i in xrange(n):
                 x = randint(1, 100)
                 L.append(x)
             fout.write(" ".join(map(str, L)) + "\n")
             for i in xrange(1, n):
                 idx = randint(0, len(ust)-1)
                 u = ust[idx]
                 idx = randint(0, len(vst)-1)
                 v = vst[idx]
                 ust.append(v)
                 vst.remove(v)
                 fout.write("%d %d\n" % (u, v))
             q = n
             fout.write("%d\n" % (q))
             L = range(1, n+1)
             shuffle(L)
             fout.write("\n".join(map(str, L)) + "\n")

 def MovDataIn():
     desFileName = "F:\eclipse_prj\workspace\hdoj\data.in"
     shutil.copyfile("data.in", desFileName)

 if __name__ == "__main__":
     GenDataIn()
     MovDataIn()