ADDED   SRM/666-U/1A-U.cpp
Index: SRM/666-U/1A-U.cpp
==================================================================
--- SRM/666-U/1A-U.cpp
+++ SRM/666-U/1A-U.cpp
@@ -0,0 +1,150 @@
+#include <iostream>
+#include <sstream>
+#include <iomanip>
+#include <vector>
+#include <string>
+#include <map>
+#include <set>
+#include <algorithm>
+#include <numeric>
+#include <iterator>
+#include <functional>
+#include <complex>
+#include <queue>
+#include <stack>
+#include <cmath>
+#include <cassert>
+#include <tuple>
+using namespace std;
+typedef long long LL;
+typedef complex<double> CMP;
+
+class WalkOverATree { public:
+	int maxNodesVisited(vector <int> parent, int L)
+	{
+		const int N = parent.size() + 1;
+		vector<vector<int>> G(N);
+		for(int i=0; i<parent.size(); ++i)
+			G[parent[i]].push_back(i+1);
+
+		vector<int> numBelow(N); {
+			function<int(int)> rec;
+			rec = [&](int v) {
+				int cnt = 1;
+				for(auto u: G[v])
+					cnt += rec(u);
+				return numBelow[v] = cnt;
+			};
+			rec(0);
+		}
+
+		function<int(int, int)> rec;
+		map<pair<int,int>, int> memo;
+		rec = [&](int v, int L) {
+			const pair<int,int> key(v, L);
+			if(memo.count(key)) return memo[key];
+
+			const vector<int>& child = G[v];
+			if(L<=0 || child.empty())
+				return 1;
+
+			int visMax = 0;
+			for(int i=0; i<child.size(); ++i) {
+				set<int> previsit;
+				previsit.insert(0);
+				for(int k=0; k<child.size(); ++k) if(i!=k) {
+					set<int> pv2 = previsit;
+					for(int z: previsit)
+						pv2.insert(z + numBelow[child[k]]);
+					previsit = pv2;
+				}
+
+				for(int p: previsit) if(p*2 <= L)
+					visMax = max(visMax, 1 + p + rec(child[i], L-p*2-1));
+			}
+			return memo[key] = visMax;
+		};
+		return rec(0, L);
+	}
+};
+
+// BEGIN CUT HERE
+#include <ctime>
+double start_time; string timer()
+ { ostringstream os; os << " (" << int((clock()-start_time)/CLOCKS_PER_SEC*1000) << " msec)"; return os.str(); }
+template<typename T> ostream& operator<<(ostream& os, const vector<T>& v)
+ { os << "{ ";
+   for(typename vector<T>::const_iterator it=v.begin(); it!=v.end(); ++it)
+   os << '\"' << *it << '\"' << (it+1==v.end() ? "" : ", "); os << " }"; return os; }
+void verify_case(const int& Expected, const int& Received) {
+ bool ok = (Expected == Received);
+ if(ok) cerr << "PASSED" << timer() << endl;  else { cerr << "FAILED" << timer() << endl;
+ cerr << "\to: \"" << Expected << '\"' << endl << "\tx: \"" << Received << '\"' << endl; } }
+#define CASE(N) {cerr << "Test Case #" << N << "..." << flush; start_time=clock();
+#define END	 verify_case(_, WalkOverATree().maxNodesVisited(parent, L));}
+int main(){
+/*
+CASE(0)
+	int parent_[] = {0, 0};
+	  vector <int> parent(parent_, parent_+sizeof(parent_)/sizeof(*parent_)); 
+	int L = 2; 
+	int _ = 2; 
+END
+*/
+CASE(1)
+	int parent_[] = {0, 0};
+	  vector <int> parent(parent_, parent_+sizeof(parent_)/sizeof(*parent_)); 
+	int L = 3; 
+	int _ = 3; 
+END
+CASE(2)
+	int parent_[] = {0, 1, 2, 3};
+	  vector <int> parent(parent_, parent_+sizeof(parent_)/sizeof(*parent_)); 
+	int L = 2; 
+	int _ = 3; 
+END
+CASE(3)
+	int parent_[] = {0,0,0,0,2,4,2,3,1};
+	  vector <int> parent(parent_, parent_+sizeof(parent_)/sizeof(*parent_)); 
+	int L = 1; 
+	int _ = 2; 
+END
+CASE(4)
+	int parent_[] = {0,0,1,2,3,2,3,1,3,0,1,8,6,8,0,5,15,0,9};
+	  vector <int> parent(parent_, parent_+sizeof(parent_)/sizeof(*parent_)); 
+	int L = 4; 
+	int _ = 5; 
+END
+CASE(5)
+	int parent_[] = {0,0,0,1,1,3,5,1,4,5,2,2,10,5,10,10,11,13,8,3,18,15,20,20,23,8,11,26,4};
+	  vector <int> parent(parent_, parent_+sizeof(parent_)/sizeof(*parent_)); 
+	int L = 26; 
+	int _ = 17; 
+END
+CASE(6)
+	int parent_[] = {0, 0, 2, 0}
+;
+	  vector <int> parent(parent_, parent_+sizeof(parent_)/sizeof(*parent_)); 
+	int L = 100; 
+	int _ = 5; 
+END
+CASE(7)
+	int parent_[] = {0, 0, 2};
+	  vector <int> parent(parent_, parent_+sizeof(parent_)/sizeof(*parent_)); 
+	int L = 4; 
+	int _ = 4; 
+END
+CASE(8)
+	int parent_[] = {0,1,2,0,4,4,4,4};
+	  vector <int> parent(parent_, parent_+sizeof(parent_)/sizeof(*parent_)); 
+	int L = 3; 
+	int _ = 4; 
+END
+CASE(9)
+	int parent_[] = {0,0,2,0,4,5};
+	  vector <int> parent(parent_, parent_+sizeof(parent_)/sizeof(*parent_)); 
+	int L = 7; 
+	int _ = 6; 
+END
+}
+// END CUT HERE

ADDED   SRM/666-U/1B.cpp
Index: SRM/666-U/1B.cpp
==================================================================
--- SRM/666-U/1B.cpp
+++ SRM/666-U/1B.cpp
@@ -0,0 +1,145 @@
+#include <iostream>
+#include <sstream>
+#include <iomanip>
+#include <vector>
+#include <string>
+#include <map>
+#include <set>
+#include <algorithm>
+#include <numeric>
+#include <iterator>
+#include <functional>
+#include <complex>
+#include <queue>
+#include <stack>
+#include <cmath>
+#include <cassert>
+#include <tuple>
+using namespace std;
+typedef long long LL;
+typedef complex<double> CMP;
+
+static const unsigned MODVAL = 1000000007;
+struct mint
+{
+	unsigned val;
+	mint():val(0){}
+	mint(int      x):val(x%MODVAL) {}
+	mint(unsigned x):val(x%MODVAL) {}
+	mint(LL       x):val(x%MODVAL) {}
+};
+mint& operator+=(mint& x, mint y) { return x = x.val+y.val; }
+mint& operator-=(mint& x, mint y) { return x = x.val-y.val+MODVAL; }
+mint& operator*=(mint& x, mint y) { return x = LL(x.val)*y.val; }
+mint operator+(mint x, mint y) { return x+=y; }
+mint operator-(mint x, mint y) { return x-=y; }
+mint operator*(mint x, mint y) { return x*=y; }
+
+vector< vector<mint> > CP_;
+mint C(int n, int k) {
+	while( CP_.size() <= n ) {
+		int nn = CP_.size();
+		CP_.push_back(vector<mint>(nn+1,1));
+		for(int kk=1; kk<nn; ++kk)
+			CP_[nn][kk] = CP_[nn-1][kk-1] + CP_[nn-1][kk];
+	}
+	return k<0 || n<k ? 0 : CP_[n][k];
+}
+
+class SumOverPermutations { public:
+	int N;
+	vector<int> memoOO, memoCO, memoCC;
+
+	int findSum(int n)
+	{
+		N = n;
+		memoOO.assign(N+1, -1);
+		memoCO.assign(N+1, -1);
+		memoCC.assign(N+1, -1);
+		return recOO(n);
+	}
+
+	int recOO(int k) {
+		if(k == 0) return 1;
+		if(k == 1) return N;
+		if(memoOO[k] != -1) return memoOO[k];
+
+		mint total = 0;
+		total += mint(N) * recCO(k-1); // left
+		total += mint(N) * recCO(k-1); // right
+		for(int i=1; i+1<k; ++i) // mid
+			total += mint(N) * recCO(i) * recCO(k-1-i) * C(k-1, i);
+		return memoOO[k] = total.val;
+	}
+
+	int recCO(int k) {
+		if(k == 0) return 1;
+		if(k == 1) return N-1;
+		if(memoCO[k] != -1) return memoCO[k];
+
+		mint total = 0;
+		total += mint(N-1) * recCO(k-1); // left
+		total += mint(N) * recCC(k-1); // right
+		for(int i=1; i+1<k; ++i) // mid
+			total += mint(N) * recCC(i) * recCO(k-1-i) * C(k-1, i);
+		return memoCO[k] = total.val;
+	}
+
+	mint recCC(int k) {
+		if(k == 0) return 1;
+		if(k == 1) return N-2;
+		if(memoCC[k] != -1) return memoCC[k];
+
+		mint total = 0;
+		total += mint(N-1) * recCC(k-1); // left
+		total += mint(N-1) * recCC(k-1); // right
+		for(int i=1; i+1<k; ++i) // mid
+			total += mint(N) * recCC(i) * recCC(k-1-i) * C(k-1, i);
+		return memoCC[k] = total.val;
+	}
+};
+
+// BEGIN CUT HERE
+#include <ctime>
+double start_time; string timer()
+ { ostringstream os; os << " (" << int((clock()-start_time)/CLOCKS_PER_SEC*1000) << " msec)"; return os.str(); }
+template<typename T> ostream& operator<<(ostream& os, const vector<T>& v)
+ { os << "{ ";
+   for(typename vector<T>::const_iterator it=v.begin(); it!=v.end(); ++it)
+   os << '\"' << *it << '\"' << (it+1==v.end() ? "" : ", "); os << " }"; return os; }
+void verify_case(const int& Expected, const int& Received) {
+ bool ok = (Expected == Received);
+ if(ok) cerr << "PASSED" << timer() << endl;  else { cerr << "FAILED" << timer() << endl;
+ cerr << "\to: \"" << Expected << '\"' << endl << "\tx: \"" << Received << '\"' << endl; } }
+#define CASE(N) {cerr << "Test Case #" << N << "..." << flush; start_time=clock();
+#define END	 verify_case(_, SumOverPermutations().findSum(n));}
+int main(){
+
+CASE(0)
+	int n = 2; 
+	int _ = 4; 
+END
+CASE(1)
+	int n = 3; 
+	int _ = 66; 
+END
+CASE(2)
+	int n = 10; 
+	int _ = 58310114; 
+END
+CASE(3)
+	int n = 3900; 
+	int _ = 940560814; 
+END
+/*
+CASE(4)
+	int n = ; 
+	int _ = ; 
+END
+CASE(5)
+	int n = ; 
+	int _ = ; 
+END
+*/
+}
+// END CUT HERE

ADDED   SRM/666-U/1C-U.cpp
Index: SRM/666-U/1C-U.cpp
==================================================================
--- SRM/666-U/1C-U.cpp
+++ SRM/666-U/1C-U.cpp
@@ -0,0 +1,186 @@
+#include <iostream>
+#include <sstream>
+#include <iomanip>
+#include <vector>
+#include <string>
+#include <map>
+#include <set>
+#include <algorithm>
+#include <numeric>
+#include <iterator>
+#include <functional>
+#include <complex>
+#include <queue>
+#include <stack>
+#include <cmath>
+#include <cassert>
+#include <tuple>
+using namespace std;
+typedef long long LL;
+typedef complex<double> CMP;
+
+static const unsigned MODVAL = 1000000007;
+struct mint
+{
+	unsigned val;
+	mint():val(0){}
+	mint(int      x):val(x%MODVAL) {}
+	mint(unsigned x):val(x%MODVAL) {}
+	mint(LL       x):val(x%MODVAL) {}
+};
+mint& operator+=(mint& x, mint y) { return x = x.val+y.val; }
+mint& operator-=(mint& x, mint y) { return x = x.val-y.val+MODVAL; }
+mint& operator*=(mint& x, mint y) { return x = LL(x.val)*y.val; }
+mint operator+(mint x, mint y) { return x+=y; }
+mint operator-(mint x, mint y) { return x-=y; }
+mint operator*(mint x, mint y) { return x*=y; }
+
+class CountBinarySequences { public:
+	int countSequences(int n, int k, vector <int> L, vector <int> R)
+	{
+		const int N = L.size();
+		vector<pair<int,int>> RNG;
+		for(int i=0; i<N; ++i)
+			RNG.emplace_back(L[i], R[i]);
+		sort(RNG.begin(), RNG.end(), [&](pair<int,int> a, pair<int,int> b){
+			if(a.second-a.first != b.second-b.first)
+				return a.second-a.first < b.second-b.first;
+			return a<b;
+		});
+
+		vector<vector<int>> child(N+1);
+		for(int i=0; i<N; ++i) {
+			int p = N;
+			for(int k=i+1; k<N; ++k)
+				if(RNG[k].first<=RNG[i].first && RNG[i].second<=RNG[k].second)
+					{p=k; break;}
+			child[p].emplace_back(i);
+		}
+		for(auto& cc: child)
+			sort(cc.begin(), cc.end(), [&](int a, int b){
+				return RNG[a].first < RNG[b].first;
+			});
+
+		RNG.emplace_back(1, n);
+
+		memo.assign((N+1)*(k+1)*(k+1), -1);
+
+		mint total = 0;
+		for(int l=0; l<=k; ++l)
+		for(int r=0; r<=k; ++r)
+			total += solve(RNG, child, k, N, l, r);
+		return total.val;
+	}
+
+	vector<int> memo;
+	int solve(
+		const vector<pair<int,int>>& RNG,
+		const vector<vector<int>>& rng_list,
+		const int K,
+		int idx, int L1, int R1) {
+		const bool must_be_even = (idx+1 == RNG.size());
+		const int key = (idx*(K+1)+L1)*(K+1)+R1;
+		if(memo[key] != -1) return memo[key];
+
+		// RNG[idx] is the current range you need to consider.
+		// rng_list[idx] is left-to-right sorted sub-ranges.
+		// the region must be sum-even if must_be_even.
+		// more than K consecutive 1's are not allowed.
+		// left-end must have exactly L1 consecutive 1's.
+		// right-end must have exactly R1 consecutive 1's.
+		return memo[key] = 0;
+	}
+};
+
+// BEGIN CUT HERE
+#include <ctime>
+double start_time; string timer()
+ { ostringstream os; os << " (" << int((clock()-start_time)/CLOCKS_PER_SEC*1000) << " msec)"; return os.str(); }
+template<typename T> ostream& operator<<(ostream& os, const vector<T>& v)
+ { os << "{ ";
+   for(typename vector<T>::const_iterator it=v.begin(); it!=v.end(); ++it)
+   os << '\"' << *it << '\"' << (it+1==v.end() ? "" : ", "); os << " }"; return os; }
+void verify_case(const int& Expected, const int& Received) {
+ bool ok = (Expected == Received);
+ if(ok) cerr << "PASSED" << timer() << endl;  else { cerr << "FAILED" << timer() << endl;
+ cerr << "\to: \"" << Expected << '\"' << endl << "\tx: \"" << Received << '\"' << endl; } }
+#define CASE(N) {cerr << "Test Case #" << N << "..." << flush; start_time=clock();
+#define END	 verify_case(_, CountBinarySequences().countSequences(n, k, L, R));}
+int main(){
+
+CASE(0)
+	int n = 4; 
+	int k = 2; 
+	int L_[] = {2};
+	  vector <int> L(L_, L_+sizeof(L_)/sizeof(*L_)); 
+	int R_[] = {3};
+	  vector <int> R(R_, R_+sizeof(R_)/sizeof(*R_)); 
+	int _ = 5; 
+END
+CASE(1)
+	int n = 4; 
+	int k = 1; 
+	int L_[] = {2};
+	  vector <int> L(L_, L_+sizeof(L_)/sizeof(*L_)); 
+	int R_[] = {2};
+	  vector <int> R(R_, R_+sizeof(R_)/sizeof(*R_)); 
+	int _ = 6; 
+END
+CASE(2)
+	int n = 6; 
+	int k = 3; 
+	int L_[] = {1, 2, 3};
+	  vector <int> L(L_, L_+sizeof(L_)/sizeof(*L_)); 
+	int R_[] = {6, 5, 4};
+	  vector <int> R(R_, R_+sizeof(R_)/sizeof(*R_)); 
+	int _ = 6; 
+END
+CASE(3)
+	int n = 1000; 
+	int k = 4; 
+	int L_[] = {10, 101, 201, 110, 121};
+	  vector <int> L(L_, L_+sizeof(L_)/sizeof(*L_)); 
+	int R_[] = {100, 200, 300, 120, 130};
+	  vector <int> R(R_, R_+sizeof(R_)/sizeof(*R_)); 
+	int _ = 444743885; 
+END
+CASE(4)
+	int n = 1; 
+	int k = 5; 
+	int L_[] = {1};
+	  vector <int> L(L_, L_+sizeof(L_)/sizeof(*L_)); 
+	int R_[] = {1};
+	  vector <int> R(R_, R_+sizeof(R_)/sizeof(*R_)); 
+	int _ = 1; 
+END
+CASE(5)
+	int n = 998; 
+	int k = 2; 
+	int L_[] = {313,365,189,913,334,360,160,931,313,402,389,328,376,47,906,383,381,927,338,178,934,933,162,332,191,188,380,912,970,360,161,179,966,405,971,381};
+	  vector <int> L(L_, L_+sizeof(L_)/sizeof(*L_)); 
+	int R_[] = {313,365,189,913,334,362,160,931,340,405,389,329,398,425,907,383,382,927,338,178,934,933,162,332,191,188,384,912,970,365,161,179,966,405,971,381};
+	  vector <int> R(R_, R_+sizeof(R_)/sizeof(*R_)); 
+	int _ = 420889003; 
+END
+/*
+CASE(6)
+	int n = ; 
+	int k = ; 
+	int L_[] = ;
+	  vector <int> L(L_, L_+sizeof(L_)/sizeof(*L_)); 
+	int R_[] = ;
+	  vector <int> R(R_, R_+sizeof(R_)/sizeof(*R_)); 
+	int _ = ; 
+END
+CASE(7)
+	int n = ; 
+	int k = ; 
+	int L_[] = ;
+	  vector <int> L(L_, L_+sizeof(L_)/sizeof(*L_)); 
+	int R_[] = ;
+	  vector <int> R(R_, R_+sizeof(R_)/sizeof(*R_)); 
+	int _ = ; 
+END
+*/
+}
+// END CUT HERE