【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。
1 /* 4358 */ 2 #include <iostream> 3 #include <sstream> 4 #include <string> 5 #include <map> 6 #include <queue> 7 #include <set> 8 #include <stack> 9 #include <vector> 10 #include <deque> 11 #include <algorithm> 12 #include <cstdio> 13 #include <cmath> 14 #include <ctime> 15 #include <cstring> 16 #include <climits> 17 #include <cctype> 18 #include <cassert> 19 #include <functional> 20 #include <iterator> 21 #include <iomanip> 22 using namespace std; 23 //#pragma comment(linker,"/STACK:102400000,1024000") 24 25 #define sti set<int> 26 #define stpii set<pair<int, int> > 27 #define mpii map<int,int> 28 #define vi vector<int> 29 #define pii pair<int,int> 30 #define vpii vector<pair<int,int> > 31 #define rep(i, a, n) for (int i=a;i<n;++i) 32 #define per(i, a, n) for (int i=n-1;i>=a;--i) 33 #define clr clear 34 #define pb push_back 35 #define mp make_pair 36 #define fir first 37 #define sec second 38 #define all(x) (x).begin(),(x).end() 39 #define SZ(x) ((int)(x).size()) 40 #define lson l, mid, rt<<1 41 #define rson mid+1, r, rt<<1|1 42 43 typedef struct { 44 int v, nxt; 45 } edge_t; 46 47 typedef struct node_t { 48 int w, id; 49 50 friend bool operator< (const node_t& a, const node_t& b) { 51 if (a.w == b.w) 52 return a.id < b.id; 53 return a.w < b.w; 54 } 55 56 } node_t; 57 58 typedef struct ques_t { 59 int l, r, id; 60 } ques_t; 61 62 const int maxn = 1e5+5; 63 const int maxv = maxn; 64 const int maxe = maxv * 2; 65 int head[maxv], l; 66 edge_t E[maxe]; 67 int Beg[maxn], End[maxn]; 68 int val[maxn], W[maxn]; 69 node_t nd[maxn]; 70 vi pvc[maxn]; 71 int dfs_clock; 72 int n, K; 73 int a[maxn]; 74 ques_t Q[maxn]; 75 int ans[maxn]; 76 77 bool compq (const ques_t& a, const ques_t& b) { 78 if (a.r == b.r) 79 return a.l < b.l; 80 return a.r < b.r; 81 } 82 83 void init() { 84 memset(head, -1, sizeof(head)); 85 memset(a, 0, sizeof(a)); 86 dfs_clock = l = 0; 87 } 88 89 void addEdge(int u, int v) { 90 E[l].v = v; 91 E[l].nxt = head[u]; 92 head[u] = l++; 93 94 E[l].v = u; 95 E[l].nxt = head[v]; 96 head[v] = l++; 97 } 98 99 void dfs(int u, int fa) { 100 int v, k; 101 102 Beg[u] = ++dfs_clock; 103 val[dfs_clock] = W[u]; 104 for (k=head[u]; k!=-1; k=E[k].nxt) { 105 v = E[k].v; 106 if (v == fa) 107 continue; 108 dfs(v, u); 109 } 110 End[u] = dfs_clock; 111 } 112 113 int lowest(int x) { 114 return x & -x; 115 } 116 117 int sum(int x) { 118 int ret = 0; 119 120 while (x) { 121 ret += a[x]; 122 x -= lowest(x); 123 } 124 125 return ret; 126 } 127 128 void update(int x, int delta) { 129 while (x <= n) { 130 a[x] += delta; 131 x += lowest(x); 132 } 133 } 134 135 void solve() { 136 int q; 137 int u, v; 138 139 sort(nd+1, nd+1+n); 140 int cnt = 1; 141 W[nd[1].id] = cnt; 142 rep(i, 2, n+1) { 143 if (nd[i].w==nd[i-1].w) { 144 W[nd[i].id] = cnt; 145 } else { 146 W[nd[i].id] = ++cnt; 147 } 148 } 149 150 dfs(1, 0); 151 152 rep(i, 0, cnt+1) { 153 pvc[i].clr(); 154 pvc[i].pb(0); 155 } 156 157 scanf("%d", &q); 158 rep(i, 0, q) { 159 scanf("%d", &u); 160 Q[i].l = Beg[u]; 161 Q[i].r = End[u]; 162 Q[i].id = i; 163 } 164 165 sort(Q, Q+q, compq); 166 int sz; 167 int j = 0; 168 169 rep(i, 1, n+1) { 170 pvc[val[i]].pb(i); 171 sz = SZ(pvc[val[i]]) - 1; 172 if (sz >= K) { 173 if (sz > K) { 174 update(pvc[val[i]][sz-K-1]+1, -1); 175 update(pvc[val[i]][sz-K]+1, 1); 176 } 177 update(pvc[val[i]][sz-K]+1, 1); 178 update(pvc[val[i]][sz-K+1]+1, -1); 179 } 180 while (j<q && Q[j].r==i) { 181 ans[Q[j].id] = sum(Q[j].l); 182 ++j; 183 } 184 } 185 186 rep(i, 0, q) 187 printf("%d\n", ans[i]); 188 } 189 190 int main() { 191 ios::sync_with_stdio(false); 192 #ifndef ONLINE_JUDGE 193 freopen("data.in", "r", stdin); 194 freopen("data.out", "w", stdout); 195 #endif 196 197 int t; 198 int u, v; 199 200 scanf("%d", &t); 201 rep(tt, 1, t+1) { 202 init(); 203 scanf("%d %d", &n, &K); 204 rep(i, 1, n+1) { 205 scanf("%d", &W[i]); 206 nd[i].id = i; 207 nd[i].w = W[i]; 208 } 209 rep(i, 1, n) { 210 scanf("%d %d", &u, &v); 211 addEdge(u, v); 212 } 213 printf("Case #%d:\n", tt); 214 solve(); 215 if (tt != t) 216 putchar('\n'); 217 } 218 219 #ifndef ONLINE_JUDGE 220 printf("time = %d.\n", (int)clock()); 221 #endif 222 223 return 0; 224 }
数据发生器。
1 from copy import deepcopy 2 from random import randint, shuffle 3 import shutil 4 import string 5 6 7 def GenDataIn(): 8 with open("data.in", "w") as fout: 9 t = 10 10 bound = 10**9 11 fout.write("%d\n" % (t)) 12 for tt in xrange(t): 13 n = randint(100, 200) 14 K = randint(1, 5) 15 fout.write("%d %d\n" % (n, K)) 16 ust = [1] 17 vst = range(2, n+1) 18 L = [] 19 for i in xrange(n): 20 x = randint(1, 100) 21 L.append(x) 22 fout.write(" ".join(map(str, L)) + "\n") 23 for i in xrange(1, n): 24 idx = randint(0, len(ust)-1) 25 u = ust[idx] 26 idx = randint(0, len(vst)-1) 27 v = vst[idx] 28 ust.append(v) 29 vst.remove(v) 30 fout.write("%d %d\n" % (u, v)) 31 q = n 32 fout.write("%d\n" % (q)) 33 L = range(1, n+1) 34 shuffle(L) 35 fout.write("\n".join(map(str, L)) + "\n") 36 37 38 def MovDataIn(): 39 desFileName = "F:\eclipse_prj\workspace\hdoj\data.in" 40 shutil.copyfile("data.in", desFileName) 41 42 43 if __name__ == "__main__": 44 GenDataIn() 45 MovDataIn()
