d335067c64 2017-07-08        kinaba: #include <iostream>
d335067c64 2017-07-08        kinaba: #include <sstream>
d335067c64 2017-07-08        kinaba: #include <iomanip>
d335067c64 2017-07-08        kinaba: #include <vector>
d335067c64 2017-07-08        kinaba: #include <string>
d335067c64 2017-07-08        kinaba: #include <map>
d335067c64 2017-07-08        kinaba: #include <set>
d335067c64 2017-07-08        kinaba: #include <algorithm>
d335067c64 2017-07-08        kinaba: #include <numeric>
d335067c64 2017-07-08        kinaba: #include <iterator>
d335067c64 2017-07-08        kinaba: #include <functional>
d335067c64 2017-07-08        kinaba: #include <complex>
d335067c64 2017-07-08        kinaba: #include <queue>
d335067c64 2017-07-08        kinaba: #include <stack>
d335067c64 2017-07-08        kinaba: #include <cmath>
d335067c64 2017-07-08        kinaba: #include <cassert>
d335067c64 2017-07-08        kinaba: #include <tuple>
d335067c64 2017-07-08        kinaba: using namespace std;
d335067c64 2017-07-08        kinaba: typedef long long LL;
d335067c64 2017-07-08        kinaba: typedef complex<double> CMP;
d335067c64 2017-07-08        kinaba: 
d335067c64 2017-07-08        kinaba: struct UnionFind
d335067c64 2017-07-08        kinaba: {
d335067c64 2017-07-08        kinaba: 	vector<int> uf, sz;
d335067c64 2017-07-08        kinaba: 	int nc;
d335067c64 2017-07-08        kinaba: 
d335067c64 2017-07-08        kinaba: 	UnionFind(int N) : uf(N), sz(N, 1), nc(N)
d335067c64 2017-07-08        kinaba: 	{
d335067c64 2017-07-08        kinaba: 		for (int i = 0; i<N; ++i) uf[i] = i;
d335067c64 2017-07-08        kinaba: 	}
d335067c64 2017-07-08        kinaba: 	int size()
d335067c64 2017-07-08        kinaba: 	{
d335067c64 2017-07-08        kinaba: 		return nc;
d335067c64 2017-07-08        kinaba: 	}
d335067c64 2017-07-08        kinaba: 	int size(int a)
d335067c64 2017-07-08        kinaba: 	{
d335067c64 2017-07-08        kinaba: 		return sz[Find(a)];
d335067c64 2017-07-08        kinaba: 	}
d335067c64 2017-07-08        kinaba: 	int Find(int a)
d335067c64 2017-07-08        kinaba: 	{
d335067c64 2017-07-08        kinaba: 		return uf[a] == a ? a : uf[a] = Find(uf[a]);
d335067c64 2017-07-08        kinaba: 	}
d335067c64 2017-07-08        kinaba: 	// Semi-compression w.o. recursion.
d335067c64 2017-07-08        kinaba: 	//{ while(uf[a] != a) a=uf[a]=uf[uf[a]]; return a; }
d335067c64 2017-07-08        kinaba: 	bool Union(int a, int b)
d335067c64 2017-07-08        kinaba: 	{
d335067c64 2017-07-08        kinaba: 		a = Find(a);
d335067c64 2017-07-08        kinaba: 		b = Find(b);
d335067c64 2017-07-08        kinaba: 		if (a != b)
d335067c64 2017-07-08        kinaba: 		{
d335067c64 2017-07-08        kinaba: 			if (sz[a] >= sz[b]) swap(a, b);
d335067c64 2017-07-08        kinaba: 			uf[a] = b;
d335067c64 2017-07-08        kinaba: 			sz[b] += sz[a];
d335067c64 2017-07-08        kinaba: 			--nc;
d335067c64 2017-07-08        kinaba: 		}
d335067c64 2017-07-08        kinaba: 		return (a != b);
d335067c64 2017-07-08        kinaba: 	}
d335067c64 2017-07-08        kinaba: };
d335067c64 2017-07-08        kinaba: 
d335067c64 2017-07-08        kinaba: static const unsigned MODVAL = 1000000007;
d335067c64 2017-07-08        kinaba: 
d335067c64 2017-07-08        kinaba: class DengklekGaneshAndTree { public:
d335067c64 2017-07-08        kinaba: 	int getCount(string labels, vector <int> parents)
d335067c64 2017-07-08        kinaba: 	{
d335067c64 2017-07-08        kinaba: 		const int N = labels.size();
d335067c64 2017-07-08        kinaba: 
d335067c64 2017-07-08        kinaba: 		vector<vector<int>> children(N);
d335067c64 2017-07-08        kinaba: 		UnionFind uf(N);
d335067c64 2017-07-08        kinaba: 		for (int i = 1; i < N; ++i) {
d335067c64 2017-07-08        kinaba: 			int u = parents[i-1], v = i;
d335067c64 2017-07-08        kinaba: 			children[u].push_back(v);
d335067c64 2017-07-08        kinaba: 			if (labels[u] == labels[v])
d335067c64 2017-07-08        kinaba: 				uf.Union(u, v);
d335067c64 2017-07-08        kinaba: 		}
d335067c64 2017-07-08        kinaba: 
d335067c64 2017-07-08        kinaba: 		vector<int> level(N);
d335067c64 2017-07-08        kinaba: 		{
d335067c64 2017-07-08        kinaba: 			function<void(int, int)> rec; rec = [&](int v, int lv) {
d335067c64 2017-07-08        kinaba: 				level[v] = lv;
d335067c64 2017-07-08        kinaba: 				for (int u : children[v])
d335067c64 2017-07-08        kinaba: 					rec(u, lv + 1);
d335067c64 2017-07-08        kinaba: 			};
d335067c64 2017-07-08        kinaba: 			rec(0, 0);
d335067c64 2017-07-08        kinaba: 		}
d335067c64 2017-07-08        kinaba: 
d335067c64 2017-07-08        kinaba: 		map<int, int> lb, ub;
d335067c64 2017-07-08        kinaba: 		for (int v = 0; v < N; ++v) {
d335067c64 2017-07-08        kinaba: 			int r = uf.Find(v), lv = level[v];
d335067c64 2017-07-08        kinaba: 			if (lb.count(r) == 0) {
d335067c64 2017-07-08        kinaba: 				lb[r] = lv;
d335067c64 2017-07-08        kinaba: 				ub[r] = lv;
d335067c64 2017-07-08        kinaba: 			}
d335067c64 2017-07-08        kinaba: 			else {
d335067c64 2017-07-08        kinaba: 				lb[r] = min(lb[r], lv);
d335067c64 2017-07-08        kinaba: 				ub[r] = max(ub[r], lv);
d335067c64 2017-07-08        kinaba: 			}
d335067c64 2017-07-08        kinaba: 		}
d335067c64 2017-07-08        kinaba: 
d335067c64 2017-07-08        kinaba: 		vector<pair<int, int>> rng;
d335067c64 2017-07-08        kinaba: 		for(auto kv : lb)
d335067c64 2017-07-08        kinaba: 			rng.emplace_back(kv.second, ub[kv.first]);
d335067c64 2017-07-08        kinaba: 		int L = *max_element(level.begin(), level.end());
d335067c64 2017-07-08        kinaba: 		return solve(rng, L);
d335067c64 2017-07-08        kinaba: 	}
d335067c64 2017-07-08        kinaba: 
d335067c64 2017-07-08        kinaba: 	// Number of ways to cover [0,L] by choosing subset of |rng|s.
d335067c64 2017-07-08        kinaba: 	int solve(vector<pair<int, int>> rng, int L) {
d335067c64 2017-07-08        kinaba: 		sort(rng.begin(), rng.end());
d335067c64 2017-07-08        kinaba: 
d335067c64 2017-07-08        kinaba: 		function<int(int, int)> rec;
d335067c64 2017-07-08        kinaba: 		vector<int> memo(rng.size() * (L+2), -1);
d335067c64 2017-07-08        kinaba: 		rec = [&](int i, int coveredUpto) {
d335067c64 2017-07-08        kinaba: 			if (i == rng.size())
d335067c64 2017-07-08        kinaba: 				return coveredUpto == L ? 1 : 0;
d335067c64 2017-07-08        kinaba: 
d335067c64 2017-07-08        kinaba: 			const int key = i*(L + 1) + (coveredUpto+1);
d335067c64 2017-07-08        kinaba: 			if (memo[key] != -1)
d335067c64 2017-07-08        kinaba: 				return memo[key];
d335067c64 2017-07-08        kinaba: 
d335067c64 2017-07-08        kinaba: 			if (coveredUpto + 2 <= rng[i].first)
d335067c64 2017-07-08        kinaba: 				return memo[key] = 0;
d335067c64 2017-07-08        kinaba: 			return memo[key] = (rec(i + 1, coveredUpto) + rec(i + 1, max(coveredUpto, rng[i].second))) % MODVAL;
d335067c64 2017-07-08        kinaba: 		};
d335067c64 2017-07-08        kinaba: 		return rec(0, -1);
d335067c64 2017-07-08        kinaba: 	}
d335067c64 2017-07-08        kinaba: };
d335067c64 2017-07-08        kinaba: 
d335067c64 2017-07-08        kinaba: // BEGIN CUT HERE
d335067c64 2017-07-08        kinaba: #include <ctime>
d335067c64 2017-07-08        kinaba: double start_time; string timer()
d335067c64 2017-07-08        kinaba:  { ostringstream os; os << " (" << int((clock()-start_time)/CLOCKS_PER_SEC*1000) << " msec)"; return os.str(); }
d335067c64 2017-07-08        kinaba: template<typename T> ostream& operator<<(ostream& os, const vector<T>& v)
d335067c64 2017-07-08        kinaba:  { os << "{ ";
d335067c64 2017-07-08        kinaba:    for(typename vector<T>::const_iterator it=v.begin(); it!=v.end(); ++it)
d335067c64 2017-07-08        kinaba:    os << '\"' << *it << '\"' << (it+1==v.end() ? "" : ", "); os << " }"; return os; }
d335067c64 2017-07-08        kinaba: void verify_case(const int& Expected, const int& Received) {
d335067c64 2017-07-08        kinaba:  bool ok = (Expected == Received);
d335067c64 2017-07-08        kinaba:  if(ok) cerr << "PASSED" << timer() << endl;  else { cerr << "FAILED" << timer() << endl;
d335067c64 2017-07-08        kinaba:  cerr << "\to: \"" << Expected << '\"' << endl << "\tx: \"" << Received << '\"' << endl; } }
d335067c64 2017-07-08        kinaba: #define CASE(N) {cerr << "Test Case #" << N << "..." << flush; start_time=clock();
d335067c64 2017-07-08        kinaba: #define END	 verify_case(_, DengklekGaneshAndTree().getCount(labels, parents));}
d335067c64 2017-07-08        kinaba: int main(){
d335067c64 2017-07-08        kinaba: 
d335067c64 2017-07-08        kinaba: CASE(0)
d335067c64 2017-07-08        kinaba: 	string labels = "seems";
d335067c64 2017-07-08        kinaba: 	int parents_[] = {0, 1, 0, 3};
d335067c64 2017-07-08        kinaba: 	  vector <int> parents(parents_, parents_+sizeof(parents_)/sizeof(*parents_));
d335067c64 2017-07-08        kinaba: 	int _ = 5;
d335067c64 2017-07-08        kinaba: END
d335067c64 2017-07-08        kinaba: CASE(1)
d335067c64 2017-07-08        kinaba: 	string labels = "like";
d335067c64 2017-07-08        kinaba: 	int parents_[] = {0, 0, 0};
d335067c64 2017-07-08        kinaba: 	  vector <int> parents(parents_, parents_+sizeof(parents_)/sizeof(*parents_));
d335067c64 2017-07-08        kinaba: 	int _ = 7;
d335067c64 2017-07-08        kinaba: END
d335067c64 2017-07-08        kinaba: CASE(2)
d335067c64 2017-07-08        kinaba: 	string labels = "a";
d335067c64 2017-07-08        kinaba: 	vector <int> parents;
d335067c64 2017-07-08        kinaba: 	int _ = 1;
d335067c64 2017-07-08        kinaba: END
d335067c64 2017-07-08        kinaba: CASE(3)
d335067c64 2017-07-08        kinaba: 	string labels = "coincidence";
d335067c64 2017-07-08        kinaba: 	int parents_[] = {0, 1, 2, 0, 2, 1, 4, 7, 7, 6};
d335067c64 2017-07-08        kinaba: 	  vector <int> parents(parents_, parents_+sizeof(parents_)/sizeof(*parents_));
d335067c64 2017-07-08        kinaba: 	int _ = 218;
d335067c64 2017-07-08        kinaba: END
d335067c64 2017-07-08        kinaba: CASE(4)
d335067c64 2017-07-08        kinaba: 	string labels = "topcoderopenroundtwobgoodluckhavefun";
d335067c64 2017-07-08        kinaba: 	int parents_[] = {0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
d335067c64 2017-07-08        kinaba: 	  vector <int> parents(parents_, parents_+sizeof(parents_)/sizeof(*parents_));
d335067c64 2017-07-08        kinaba: 	int _ = 147418098;
d335067c64 2017-07-08        kinaba: END
d335067c64 2017-07-08        kinaba: /*
d335067c64 2017-07-08        kinaba: CASE(5)
d335067c64 2017-07-08        kinaba: 	string labels = ;
d335067c64 2017-07-08        kinaba: 	int parents_[] = ;
d335067c64 2017-07-08        kinaba: 	  vector <int> parents(parents_, parents_+sizeof(parents_)/sizeof(*parents_));
d335067c64 2017-07-08        kinaba: 	int _ = ;
d335067c64 2017-07-08        kinaba: END
d335067c64 2017-07-08        kinaba: CASE(6)
d335067c64 2017-07-08        kinaba: 	string labels = ;
d335067c64 2017-07-08        kinaba: 	int parents_[] = ;
d335067c64 2017-07-08        kinaba: 	  vector <int> parents(parents_, parents_+sizeof(parents_)/sizeof(*parents_));
d335067c64 2017-07-08        kinaba: 	int _ = ;
d335067c64 2017-07-08        kinaba: END
d335067c64 2017-07-08        kinaba: */
d335067c64 2017-07-08        kinaba: }
d335067c64 2017-07-08        kinaba: // END CUT HERE