From 2173d3fdeffc0da5dde2c063a2ed0a90f58dc4e1 Mon Sep 17 00:00:00 2001
From: tomsmeding <tom.smeding@gmail.com>
Date: Sun, 15 May 2016 23:19:42 +0200
Subject: Initial

---
 solve.cpp | 266 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 266 insertions(+)
 create mode 100644 solve.cpp

(limited to 'solve.cpp')

diff --git a/solve.cpp b/solve.cpp
new file mode 100644
index 0000000..0107521
--- /dev/null
+++ b/solve.cpp
@@ -0,0 +1,266 @@
+#include <iostream>
+#include <string>
+#include <cstdlib>
+#include <cstdint>
+#include <cassert>
+
+using namespace std;
+
+
+class Board{
+	int8_t *bd;
+	
+	inline int8_t& operator[](int i){return bd[i];}
+	inline int8_t& at(int x,int y,bool tr=false){
+		if(tr)return bd[S*x+y];
+		else return bd[S*y+x];
+	}
+
+	string row(int i,bool tr){return (tr?"column ":"row ")+to_string(i+1);}
+	string column(int i,bool tr){return (tr?"row ":"column ")+to_string(i+1);}
+	string pos(int x,int y,bool tr){return "("+to_string(tr?y+1:x+1)+","+to_string(tr?x+1:y+1)+")";}
+
+	bool solvefullrows(bool tr){
+		bool changed=false;
+		for(int y=0;y<S;y++){
+			int n0=0,n1=0,ex=-1;
+			for(int x=0;x<S;x++){
+				switch(at(x,y,tr)){
+					case -1: ex=x; break;
+					case 0: n0++; break;
+					case 1: n1++; break;
+				}
+			}
+			if(ex!=-1&&n0+n1==S-1){
+				bool v=n0<S/2?0:1;
+				at(ex,y,tr)=v;
+				cerr<<"Fill "<<row(y,tr)<<": "<<pos(ex,y,tr)<<" -> "<<v<<endl<<*this<<endl<<endl;
+				changed=true;
+			}
+		}
+		return changed;
+	}
+	bool solvefullrows(){return solvefullrows(false)|solvefullrows(true);}
+
+	bool completerows(bool tr){
+		bool changed=false;
+		for(int y=0;y<S;y++){
+			int n0=0,n1=0;
+			for(int x=0;x<S;x++){
+				switch(at(x,y,tr)){
+					case 0: n0++; break;
+					case 1: n1++; break;
+				}
+			}
+			if(n0==S/2&&n1<S/2){
+				cerr<<"Complete "<<row(y,tr)<<" with ones:";
+				for(int x=0;x<S;x++)if(at(x,y,tr)==-1){
+					at(x,y,tr)=1;
+					cerr<<' '<<pos(x,y,tr)<<" -> 1";
+				}
+				cerr<<endl<<*this<<endl<<endl;
+				changed=true;
+			} else if(n1==S/2&&n0<S/2){
+				cerr<<"Complete "<<row(y,tr)<<" with zeros:";
+				for(int x=0;x<S;x++)if(at(x,y,tr)==-1){
+					at(x,y,tr)=0;
+					cerr<<' '<<pos(x,y,tr)<<" -> 0";
+				}
+				cerr<<endl<<*this<<endl<<endl;
+				changed=true;
+			}
+		}
+		return changed;
+	}
+	bool completerows(){return completerows(false)|completerows(true);}
+
+	bool solveequalrows(bool tr){
+		bool changed=false;
+		for(int y1=0;y1<S;y1++){
+			for(int y2=y1+1;y2<S;y2++){
+				int x,n1=0,n2=0,exa=-1,exb=-1;
+				for(x=0;x<S;x++){
+					int v1=at(x,y1,tr),v2=at(x,y2,tr);
+					n1+=v1!=-1; n2+=v2!=-1;
+					if(v1==-1||v2==-1){
+						exa=exb;
+						exb=x;
+					}
+					if(v1!=-1&&v2!=-1&&v1!=v2)break;
+				}
+				if(x==S){
+					if(n1==S&&n2==S-2){
+						at(exa,y2,tr)=!at(exa,y1,tr);
+						at(exb,y2,tr)=!at(exb,y1,tr);
+						cerr<<"Prevent "<<row(y2,tr)<<" from matching "<<row(y1,tr)
+						    <<": "<<pos(exa,y2,tr)<<" -> "<<!at(exa,y1,tr)
+						    <<", "<<pos(exb,y2,tr)<<" -> "<<!at(exb,y1,tr)<<endl<<*this<<endl<<endl;
+						changed=true;
+					} else if(n1==S-2&&n2==S){
+						at(exa,y1,tr)=!at(exa,y2,tr);
+						at(exb,y1,tr)=!at(exb,y2,tr);
+						cerr<<"Prevent "<<row(y1,tr)<<" from matching "<<row(y2,tr)
+						    <<": "<<pos(exa,y1,tr)<<" -> "<<!at(exa,y2,tr)
+						    <<", "<<pos(exb,y1,tr)<<" -> "<<!at(exb,y2,tr)<<endl<<*this<<endl<<endl;
+						changed=true;
+					}
+				}
+			}
+		}
+		return changed;
+	}
+	bool solveequalrows(){return solveequalrows(false)|solveequalrows(true);}
+
+	bool solvetrits(bool tr){
+		bool changed=false;
+		for(int y=0;y<S;y++){
+			for(int x=0;x<S;x++){
+				if(at(x,y,tr)!=-1)continue;
+				bool opp;
+				if(x>0&&x<S-1&&at(x-1,y,tr)!=-1&&at(x-1,y,tr)==at(x+1,y,tr))opp=at(x-1,y,tr);
+				else if(x>1&&at(x-2,y,tr)!=-1&&at(x-2,y,tr)==at(x-1,y,tr))opp=at(x-1,y,tr);
+				else if(x<S-2&&at(x+2,y,tr)!=-1&&at(x+2,y,tr)==at(x+1,y,tr))opp=at(x+1,y,tr);
+				else continue;
+				at(x,y,tr)=!opp;
+				cerr<<"Prevent trit: "<<pos(x,y,tr)<<" -> "<<!opp<<endl<<*this<<endl<<endl;
+				changed=true;
+			}
+		}
+		return changed;
+	}
+	bool solvetrits(){return solvetrits(false)|solvetrits(true);}
+
+
+	bool verifycounts(bool tr){
+		for(int y=0;y<S;y++){
+			int n0=0,n1=0;
+			for(int x=0;x<S;x++){
+				switch(at(x,y,tr)){
+					case 0: n0++; break;
+					case 1: n1++; break;
+				}
+			}
+			if(n0!=S/2||n1!=S/2){
+				cerr<<"Count verification failure at "<<row(y,tr)<<endl;
+				return false;
+			}
+		}
+		return true;
+	}
+	bool verifycounts(){return verifycounts(false)&&verifycounts(true);}
+
+	bool verifytrits(bool tr){
+		for(int y=0;y<S;y++){
+			int pr=-1,n=0;
+			for(int x=0;x<S;x++){
+				int v=at(x,y,tr);
+				if(pr==v){
+					n++;
+					if(pr!=-1&&n>=3){
+						cerr<<"Trit verification failure at "<<pos(x,y,tr)<<endl;
+						return false;
+					}
+				} else {
+					pr=v;
+					n=0;
+				}
+			}
+		}
+		return true;
+	}
+	bool verifytrits(){return verifytrits(false)&&verifytrits(true);}
+
+	bool verifyequalrows(bool tr){
+		for(int y1=0;y1<S;y1++){
+			for(int y2=y1+1;y2<S;y2++){
+				int x;
+				for(x=0;x<S;x++){
+					if(at(x,y1,tr)!=at(x,y2,tr))break;
+				}
+				if(x==S){
+					cerr<<"Equal row verification failure on "<<row(y1,tr)<<" and "<<row(y2,tr)<<endl;
+					return false;
+				}
+			}
+		}
+		return true;
+	}
+	bool verifyequalrows(){return verifyequalrows(false)&&verifyequalrows(true);}
+
+public:
+	const int S;
+
+	Board(int S):S(S){
+		if(S<2||S%2==1){
+			cerr<<"Invalid board size "<<S<<endl;
+			exit(1);
+		}
+		bd=new int8_t[S*S];
+	}
+	~Board(){
+		delete[] bd;
+	}
+
+	inline int8_t operator[](int i) const {return bd[i];}
+	inline int8_t at(int x,int y) const {return bd[S*y+x];}
+
+	void solve(){
+		while(solvefullrows()
+		     |completerows()
+		     |solveequalrows()
+		     |solvetrits());
+	}
+
+	bool verify(){
+		return verifycounts()&&verifytrits()&&verifyequalrows();
+	}
+
+	friend istream& operator>>(istream &is,Board &bd);
+	friend ostream& operator<<(ostream &os,const Board &bd);
+};
+
+istream& operator>>(istream &is,Board &bd){
+	char c;
+	for(int i=0;i<bd.S*bd.S;i++){
+		is>>c;
+		if(c=='0')bd[i]=0;
+		else if(c=='1')bd[i]=1;
+		else if(c=='.'||c=='_')bd[i]=-1;
+		else {
+			cerr<<"Invalid char inputted: '"<<c<<'\''<<endl;
+			exit(1);
+		}
+	}
+	return is;
+}
+
+ostream& operator<<(ostream &os,const Board &bd){
+	for(int y=0;y<bd.S;y++){
+		if(y!=0)os<<'\n';
+		for(int x=0;x<bd.S;x++){
+			if(x!=0)os<<' ';
+			switch(bd.at(x,y)){
+				case -1: os<<'.'; break;
+				case 0: os<<'0'; break;
+				case 1: os<<'1'; break;
+				default: os<<'?'; break;
+			}
+		}
+	}
+	return os;
+}
+
+int main(){
+	int S;
+	cin>>S;
+	Board bd(S);
+	cin>>bd;
+	cerr<<bd<<endl<<endl;
+	bd.solve();
+	if(!bd.verify()){
+		cerr<<"VERIFICATION FAILURE!"<<endl;
+		return 1;
+	}
+	cout<<bd<<endl;
+	return 0;
+}
-- 
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