changed algorythm (unfinished)

source/solver.c

 /* solver.c */
-/* Last Change: 2018/07/16 (Mon) 10:05:50. */
+/* Last Change: 2018/08/26 (Sun) 05:04:28. */
+
+#define MAX_ATTEMPS lines*10
 
 #include<stdio.h>
-/* #include<stdlib.h> */
+#include<stdlib.h>
 #include<string.h>
 /* #include<limits.h> */
 /* #include<math.h> */
-/* #include<time.h> */
+#include<time.h>
 
 int board[8][72][72]={};
-int avail[8][72][72]={};
+int avail[8][72][72]={}; //start=3,path=2,avail=1,nonavail=0,goal=-1
+int connected[8*72*72/2+1]={};
 int depth,height,width;
 int lines;
+int searchorder[6];
 //z,y,x
 
-void reset(void){
-	int i,j,k;
-	for(i=0;i<depth;i++)
-		for(j=0;j<height;j++)
-			for(k=0;k<width;k++)
-				board[i][j][k]=0;
-	return;
-}
-
 void read(void){
 	int x,y,z,i;
 	char c,str[8];
@@ -78,35 +73,48 @@ void read(void){
 	return;
 }
 
-int order(int num){ //1-lines -> 1-lines
-	return num;
+int randline(void){ //1-lines -> 1-lines
+	return rand()%lines+1;
 }
 
-int connected(int line){
-	int i,j,k;
-	for(i=0;i<depth;i++)
-		for(j=0;j<height;j++)
-			for(k=0;k<width;k++)
-				if(board[i][j][k]==line)
-					return 1;
-	return 0;
+void shuffle(int array[]){
+	for(int i=0;i<6;i++){
+		int j=rand()%6;
+		int t=array[i];
+		array[i]=array[j];
+		array[j]=t;
+	}
 }
 
 int available(int startx,int starty, int startz){
-	if(avail[startz][starty][startx]==-1)
+	if(avail[startz][starty][startx]==-1) //goal
 		return 1;
+	if(avail[startz][starty][startx]==2) //visited
+		return 0;
+	avail[startz][starty][startx]=2;
+	shuffle(searchorder);
+	int i;
+	for(i=0;i<6;i++)
+		switch(searchorder[i]){
+			case 0:
 				if(startx>0&&available(startx-1,starty,startz))
 					return 1;
+			case 1:
 				if(starty>0&&available(startx,starty-1,startz))
 					return 1;
+			case 2:
 				if(startz>0&&available(startx,starty,startz-1))
 					return 1;
+			case 3:
 				if(startx<depth&&available(startx+1,starty,startz))
 					return 1;
+			case 4:
 				if(starty<height&&available(startx,starty+1,startz))
 					return 1;
+			case 5:
 				if(startz<width&&available(startx,starty,startz+1))
 					return 1;
+		}
 	return 0;
 }
 
@@ -116,28 +124,35 @@ int connectable(int linea,int lineb){
 	for(i=0;i<depth;i++)
 		for(j=0;j<height;j++)
 			for(k=0;k<width;k++)
-				if(board[i][j][k]==-linea)
+				if(board[i][j][k]==-linea){
 					if(notfound){
 						notfound=0;
-						avail[i][j][k]=1;
 						startz=i;
 						starty=j;
 						startx=k;
-					}else
-						avail[i][j][k]=-1;
-					else if(board[i][j][k]==0||board[i][j][k]==lineb||board[i][j][k]==linea)
+						avail[startz][starty][startx]=3;
+					}else{
+						avail[i][j][k]=-1; //goal
+					}
+				}else if(board[i][j][k]==0||board[i][j][k]==lineb||board[i][j][k]==linea){
 					avail[i][j][k]=1;
-					else
+				}else{
 					avail[i][j][k]=0;
+				}
 	if(startx==-1||starty==-1||startz==-1){
-		printf("Error!\n");
+		printf("Error: Line %d\n",linea);
 		return 0;
 	}
 	return available(startx,starty,startz);
 }
 
-void actuallyconnect(int num){
-	//REQUIRED
+void connect(int num){
+	int i,j,k;
+	for(i=0;i<depth;i++)
+		for(j=0;j<height;j++)
+			for(k=0;k<width;k++)
+				if(avail[i][j][k]==2)
+					board[i][j][k]=num;
 	return;
 }
 
@@ -151,25 +166,35 @@ void delete(int line){
 	return;
 }
 
-void connect(int num){
-	int i;
-	if(connectable(order(num),0))
-		actuallyconnect(order(num));
-	else
-		for(i=num-1;i>=1;i--)
-			if(connectable(order(num),order(i))){
-				delete(order(i));
-				actuallyconnect(order(num));
-				connect(i);
+int solve(void){ //return 1 when solved, 0 when cannot
+	int i,j,linea,lineb;
+	for(i=0;i<MAX_ATTEMPS;i++){
+		linea=randline();
+		if(connected[linea])
+			continue;
+		if(connectable(linea,0)){
+			connect(linea);
+			connected[linea]=1;
+			connected[0]++;
+			if(connected[0]==lines)
+				return 1;
 		}
-	return;
-}
-
-void solve(void){
-	int i;
-	for(i=1;i<=lines;i++)
-		connect(i);
-	return;
+		else{
+			for(j=0;j<lines*2;j++){
+				lineb=randline();
+				if(connectable(linea,lineb)){
+					delete(lineb);
+					connect(linea);
+					connected[linea]=1;
+					connected[lineb]=0;
+					break;
+				}
+				if(j==MAX_ATTEMPS/2-1)
+					return 0;
+			}
+		}
+	}
+	return 0;
 }
 
 void write(void){
@@ -193,10 +218,15 @@ void write(void){
 }
 
 int main(void){
-	/* reset(); */
+	int i;
+	srand((unsigned)time(NULL));
 	read();
-	solve();
+	for(i=0;i<6;i++)
+		searchorder[i]=i;
+	if(solve())
 		write();
+	else
+		printf("Cannot solve!\n");
 	return 0;
 }