ADDED   SRM/625-U/1A.cpp
Index: SRM/625-U/1A.cpp
==================================================================
--- SRM/625-U/1A.cpp
+++ SRM/625-U/1A.cpp
@@ -0,0 +1,110 @@
+#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 PalindromePermutations { public:
+	double palindromeProbability(string word)
+	{
+		map<char, int> cnt;
+		for(char c: word) cnt[c]++;
+
+		vector<int> ns;
+		for(auto cn: cnt) ns.emplace_back(cn.second);
+
+		return solve(ns);
+	}
+
+	double solve(vector<int> c)
+	{
+		if(count_if(c.begin(), c.end(), [&](int x){return x%2==1;}) >= 2)
+			return 0.0;
+		return rec(c);
+	}
+
+	double rec(vector<int> c)
+	{
+		if(c.size() <= 1)
+			return 1.0;
+
+		int n = accumulate(c.begin(), c.end(), 0);
+		int n2 = n/2;
+		int k = c.back();
+		int k2 = k/2;
+		c.pop_back();
+		return C(n2,k2) / C(n,k) * rec(c);
+	}
+
+	double C(int n, int k)
+	{
+		double v = 1.0;
+		for(int i=1; i<=k; ++i)
+			v = v * (n+1-i) / i;
+		return v;
+	}
+};
+
+// 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 double& Expected, const double& Received) {
+ bool ok = (abs(Expected - Received) < 1e-9);
+ 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(_, PalindromePermutations().palindromeProbability(word));}
+int main(){
+
+CASE(0)
+	string word = "haha"; 
+	double _ = 0.3333333333333333; 
+END
+CASE(1)
+	string word = "xxxxy"; 
+	double _ = 0.2; 
+END
+CASE(2)
+	string word = "xxxx"; 
+	double _ = 1.0; 
+END
+CASE(3)
+	string word = "abcde"; 
+	double _ = 0.0; 
+END
+CASE(4)
+	string word = "hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhff"; 
+	double _ = 0.025641025641025637; 
+END
+/*
+CASE(5)
+	string word = ; 
+	double _ = ; 
+END
+CASE(6)
+	string word = ; 
+	double _ = ; 
+END
+*/
+}
+// END CUT HERE

ADDED   SRM/625-U/1B.cpp
Index: SRM/625-U/1B.cpp
==================================================================
--- SRM/625-U/1B.cpp
+++ SRM/625-U/1B.cpp
@@ -0,0 +1,260 @@
+#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;
+
+template<typename Vert=int, typename Flow=int, int NV=2048>
+class MaxFlow
+{
+	vector<int> G[NV];
+	Flow F[NV][NV];
+
+public:
+	void addEdge( Vert s, Vert t, Flow f )
+	{
+		G[s].push_back(t);
+		G[t].push_back(s);
+		F[s][t] = f;
+		F[t][s] = 0;
+	}
+
+	Flow calc( Vert S, Vert D )
+	{
+		for( Flow total=0 ;; ) {
+			// Do BFS and compute the level for each node.
+			int LV[NV] = {0};
+			vector<int> Q(1, S);
+			for(int lv=1; !Q.empty(); ++lv) {
+				vector<int> Q2;
+				for(size_t i=0; i!=Q.size(); ++i) {
+					const vector<int>& ne = G[Q[i]];
+					for(size_t j=0; j!=ne.size(); ++j)
+						if( F[Q[i]][ne[j]] && !LV[ne[j]] && ne[j]!=S )
+							LV[ne[j]]=lv, Q2.push_back(ne[j]);
+				}
+				Q.swap(Q2);
+			}
+
+			// Destination is now unreachable. Done.
+			if( !LV[D] )
+				return total;
+
+			// Iterating DFS.
+			bool blocked[NV] = {};
+			total += dinic_dfs( S, D, LV, 0x7fffffff, blocked );
+		}
+	}
+
+private:
+	Flow dinic_dfs( int v, int D, int LV[], Flow flow_in, bool blocked[] )
+	{
+		Flow flow_out = 0;
+		for(size_t i=0; i!=G[v].size(); ++i) {
+			int u = G[v][i];
+			if( LV[v]+1==LV[u] && F[v][u] ) {
+				Flow f = min(flow_in-flow_out, F[v][u]);
+				if( u==D || !blocked[u] && (f=dinic_dfs(u,D,LV,f,blocked))>0 ) {
+					F[v][u]  -= f;
+					F[u][v]  += f;
+					flow_out += f;
+					if( flow_in == flow_out ) return flow_out;
+				}
+			}
+		}
+		blocked[v] = (flow_out==0);
+		return flow_out;
+	}
+};
+
+class BlockTheBlockPuzzle { public:
+	int minimumHoles(vector <string> board)
+	{
+		const int H = board.size();
+		const int W = board[0].size();
+		const int INF = 2500;
+		for(int gy=0; gy<H; ++gy)
+		for(int gx=0; gx<W; ++gx) if(board[gy][gx] == '$')
+		{
+			map<pair<int,int>, int> id;
+			for(int y=gy%3; y<H; y+=3)
+			for(int x=gx%3; x<W; x+=3)
+			{
+				int new_id = id.size();
+				id[make_pair(y,x)] = new_id;
+			}
+
+			int N = id.size();
+			MaxFlow<>* mf = new MaxFlow<>;
+			enum {IN, OUT};
+
+			int Goal;
+			vector<int> Start;
+			for(int y=gy%3; y<H; y+=3)
+			for(int x=gx%3; x<W; x+=3)if(board[y][x]!='H')
+			{
+				int v1 = id[make_pair(y,x)];
+				if(board[y][x]=='$')
+					Goal = v1;
+				if(board[y][x]=='b')
+					Start.push_back(v1);
+				
+				int e = (board[y][x]=='.' ? 1 : INF);
+				mf->addEdge(v1*2+IN, v1*2+OUT, e);
+				//cerr << v1 << " -- " << e << " -- " << v1 << endl;
+
+				const int dy[] = {+1,0};
+				const int dx[] = {0,+1};
+				for(int d=0; d<2; ++d)
+				{
+					int Y = y+dy[d]*3;
+					int X = x+dx[d]*3;
+					if(0<=Y&&Y<H&&0<=X&&X<W&&board[Y][X]!='H')
+					{
+						int v2 = id[make_pair(Y,X)];
+
+						int y1=y+dy[d]*1;
+						int x1=x+dx[d]*1;
+						int y2=y+dy[d]*2;
+						int x2=x+dx[d]*2;
+						int e = INF;
+						if(board[y1][x1]!='b'&&board[y2][x2]!='b')
+							e = (board[y1][x1]=='.')+(board[y2][x2]=='.');
+						if(e) {
+							mf->addEdge(v1*2+OUT, v2*2+IN, e);
+							mf->addEdge(v2*2+OUT, v1*2+IN, e);
+							//cerr << v1 << " -- " << e << " -- " << v2 << endl;
+						}
+					}
+				}
+			}
+
+			for(int v: Start) {
+				//cerr << "S: " << v << endl;
+				mf->addEdge(v*2+OUT, N*2+IN, INF);
+			}
+			//cerr << "G: " << Goal << endl;
+			int ans = mf->calc(Goal*2+OUT, N*2+IN);
+			delete mf;
+			return ans>=INF ? -1 : ans;
+		}
+		return -1;
+	}
+};
+
+// 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(_, BlockTheBlockPuzzle().minimumHoles(board));}
+int main(){
+
+CASE(0)
+	string board_[] = {"b..$",
+ "....",
+ "HHHH",
+ "HHHH"};
+	  vector <string> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
+	int _ = 2; 
+END
+CASE(1)
+	string board_[] = {"............H..",
+ "...............",
+ "...............",
+ "HHH$HHH.....H..",
+ "HHHHHHH........",
+ "HHHHHHHH.......",
+ "......b..H.....",
+ "...............",
+ "...............",
+ "...H..H..H.....",
+ "...............",
+ "...............",
+ "...............",
+ "...............",
+ "..............."};
+	  vector <string> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
+	int _ = 0; 
+END
+CASE(2)
+	string board_[] = {"............H..",
+ "...............",
+ "...............",
+ "HHH$HHH........",
+ "HHHHHHH........",
+ "HHHHHHHH.......",
+ "......b..H.....",
+ "...............",
+ "...............",
+ "...H..H..H.....",
+ "...............",
+ "...............",
+ "...............",
+ "...............",
+ "..............."};
+	  vector <string> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
+	int _ = 1; 
+END
+CASE(3)
+	string board_[] = {"b..$...",
+ "...H...",
+ ".......",
+ "b..b..b",
+ "...H...",
+ ".......",
+ "b..b..b"}
+
+;
+	  vector <string> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
+	int _ = 4; 
+END
+CASE(4)
+	string board_[] = {"b..b..b",
+ "..b..b.",
+ ".......",
+ "b..$bbb",
+ ".b.....",
+ "....b..",
+ "b..b..b"}
+;
+	  vector <string> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
+	int _ = -1; 
+END
+/*
+CASE(5)
+	string board_[] = ;
+	  vector <string> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
+	int _ = ; 
+END
+CASE(6)
+	string board_[] = ;
+	  vector <string> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
+	int _ = ; 
+END
+*/
+}
+// END CUT HERE