solve 2, 3, (6), 7

.gitignore

-# Ignore ctags
-tags
-tags.lock
-
-# Ignore binaries
-.x_*
-*.gch
-*.out

solver.c

 /* solver.c */
-/* Last Change: 2019/07/23 (Tue) 17:13:18. */
+/* Last Change: 2019/07/25 (Thu) 14:03:43. */
 
 #include<stdio.h>
 #include<limits.h>
+#include<stdlib.h>
+#include<time.h>
 #include"solver.h"
 #include"io.h"
-/* #include<stdlib.h> */
 /* #include<string.h> */
 /* #include<math.h> */
-/* #include<time.h> */
-#define DEBUG 0
-#define abs(a) ((a) < 0 ? - (a) : (a))
+#define DEBUG 1
+#define ABS(a) ((a) < 0 ? - (a) : (a))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
 
 /* short int connected[MAXLINE+1]={0}; //if line connected:2, if one end:1, otherwize:0 */
 short int board_beta[MAXSIZE][MAXSIZE]; //big board data
@@ -20,13 +21,30 @@ short int point[MAXBLOCK+1]; //XYZ
 //X: search priority, Y: number of edges in board, Z: number of edges in block
 short int first_block=1;
 short int costrank[1+MAXBLOCK*MAXBLOCK][2]; //ranking of cost: block being in (costrank[ranking][0],costrank[ranking][0])
+short int rdm[MAXBLOCK+1]; //random no
+short int attempts=1;
 
 void print_board_beta(void){
 	short int i,j;
+	short int minw=MAXSIZE-1,maxw=0,minh=MAXSIZE-1,maxh=0;
 	for(i=0;i<MAXSIZE;i++){
 		for(j=0;j<MAXSIZE;j++){
-			printf("%d",board_beta[j][i]);
-			if(j==MAXSIZE-1)
+			if(board_beta[i][j]){
+				if(i>maxw)
+					maxw=i;
+				if(i<minw)
+					minw=i;
+				if(j>maxh)
+					maxh=j;
+				if(j<minh)
+					minh=j;
+			}
+		}
+	}
+	for(i=minh;i<=maxh;i++){
+		for(j=minw;j<=maxw;j++){
+			printf("%6d",board_beta[j][i]);
+			if(j==maxw)
 				printf("\n");
 			else
 				printf(",");
@@ -35,33 +53,48 @@ void print_board_beta(void){
 	return;
 }
 
-void update_ranks(void){
-	short int i,j;
+void shuffle_random(short int seed){ //edit this to randomly place blocks
+	short int i,r,tmp;
+	srand(seed);
+	for(i=1;i<=blocks;i++)
+		rdm[i]=i;
 	for(i=1;i<=blocks;i++){
-		rank[i]=1;
+		r=rand()%blocks+1;
+		tmp=rdm[i];
+		rdm[i]=rdm[r];
+		rdm[r]=tmp;
 	}
+	return;
+}
+
+void update_ranks(void){
+	short int i,j,blocksrank[MAXBLOCK+1];
 	for(i=1;i<=blocks;i++){
-		for(j=1;j<=blocks;j++)
-			if(point[i]<point[j])
-				rank[i]++;
-			else if(point[i]==point[j] && i>j)
-				rank[i]++;
+		blocksrank[i]=1;
 	}
-	if(DEBUG){
 	for(i=1;i<=blocks;i++){
-			printf("%d ",rank[i]);
+		for(j=1;j<=blocks;j++){
+			if(point[rdm[i]]<point[rdm[j]])
+				blocksrank[rdm[i]]++;
+			else if(point[rdm[i]]==point[rdm[j]] && i>j)
+				blocksrank[rdm[i]]++;
+			/* else */
+			/* printf("%d %d no\n",rdm[i],rdm[j]); */
 		}
-		printf("\n");
 	}
+	for(i=1;i<=blocks;i++)
+		rank[blocksrank[i]]=i;
 	return;
 }
 
 void reset(void){ //excluding init_points
 	short int i,j;
-	for(i=0;i<MAXSIZE;i++)
+	for(i=0;i<MAXSIZE;i++) //clear board
 		for(j=0;j<MAXSIZE;j++)
 			board_beta[i][j]=0;
-	for(i=1;i<=blocks;i++){
+	for(i=1;i<=blocks;i++){ //clear blocks' places
+		if(point[i]<0)
+			point[i]=-point[i];
 		block_data[i][0][0]=-1;
 		block_data[i][0][1]=-1;
 		point[i]-=((point[i]/10)%10)*10; //reset Y
@@ -80,25 +113,38 @@ void init_points(void){ //use only once
 		point[i]=0;
 		for(j=1;j<=4;j++)
 			if(block_data[i][j][2]>0) //if edge exists
+				point[i]+=2;
+		if(point[i]==0)
 			point[i]++;
 	}
 	update_ranks();
 	return;
 }
 
-void add_point(short int blockid,short int lineid){ //use only once
-	short int i,j;
+void add_point(short int blockid){
+	short int i,j,k;
 	for(i=1;i<=blocks;i++)
-		if(i!=blockid)
+		if(i!=blockid&&point[i]>0)
 			for(j=1;j<=4;j++)
-				if(block_data[i][j][2]==lineid) //if edge exists
+				for(k=1;k<=4;k++)
+					if(block_data[i][j][2]==block_data[blockid][k][2]&&block_data[blockid][k][2]>0)
 						point[i]+=10;
+	update_ranks();
+	return;
+}
+
+void sub_point(short int blockid){
+	short int i,j,k;
+	for(i=1;i<=blocks;i++)
+		if(i!=blockid&&point[i]>0)
+			for(j=1;j<=4;j++)
+				for(k=1;k<=4;k++)
+					if(block_data[i][j][2]==block_data[blockid][k][2]&&block_data[blockid][k][2]>0)
+						point[i]+=10;
+	update_ranks();
 	return;
 }
 
-/* short int random(short int id){ //edit this to randomly place blocks */
-/* return id; */
-/* } */
 
 short int search_placable(short int blockid){ //calc the cost (sum of Euclidean distance of lines), returns the number of places
 	short int cost[MAXSIZE][MAXSIZE][2]; //cost[x][y][0]:cost, cost[x][y][1]:rank
@@ -116,7 +162,7 @@ short int search_placable(short int blockid){ //calc the cost (sum of Euclidean
 			for(j=0;j<MAXSIZE;j++)
 				if(board_beta[i][j]>0 && board_beta[i][j]==block_data[blockid][k][2]){
 					place[k][0]=i-block_data[blockid][k][0];
-					place[k][1]=i-block_data[blockid][k][1];
+					place[k][1]=j-block_data[blockid][k][1];
 				}
 		}
 		/* printf("%d, %d\n",place[k][0],place[k][1]); */
@@ -140,23 +186,19 @@ short int search_placable(short int blockid){ //calc the cost (sum of Euclidean
 				cost[i][j][0]=-1;
 			else{
 				cost[i][j][0]=0;
-				/* printf("%d, %d\n",abs(i-place[k][0]),abs(j-place[k][1])); */
-				/* printf("%d\n",abs(i-place[k][0])+abs(j-place[k][1])); */
 				for(k=1;k<=4;k++){
 					if(place[k][0]!=SHRT_MIN)
-						cost[i][j][0]+=abs(i-place[k][0]);
+						cost[i][j][0]+=ABS(i-place[k][0]);
 					if(place[k][1]!=SHRT_MIN)
-						cost[i][j][0]+=abs(j-place[k][1]);
+						cost[i][j][0]+=ABS(j-place[k][1]);
 				}
 				if(cost[i][j][0]==0)
-					cost[i][j][0]=abs(i-MAXSIZE/2)+abs(j-MAXSIZE/2);
-				/* cost[i][j][0]+=(short int)abs((int)(i-place[k][0]))+(short int)abs((int)(j-place[k][1])); */
+					cost[i][j][0]=MAX(MAX(ABS(i-MAXSIZE/2),ABS(j-MAXSIZE/2)),MAX(ABS(i+blockw-MAXSIZE/2),ABS(j+blockh-MAXSIZE/2)));//*100+ABS(i-MAXSIZE/2)+ABS(j-MAXSIZE/2)+ABS(i+blockw-MAXSIZE/2)+ABS(j+blockh-MAXSIZE/2);
 				cost[i][j][0]=10000-cost[i][j][0];
 				/* printf("%d\n",cost[i][j][0]); */
 			}
 		}
 	}
-	//ok
 	/* calc costrank */
 	for(i=0;i<MAXSIZE;i++)
 		for(j=0;j<MAXSIZE;j++)
@@ -177,7 +219,212 @@ short int search_placable(short int blockid){ //calc the cost (sum of Euclidean
 	return index-1;
 }
 
-short int try_wire(short int blockid){
+void erase_line(short int lineid){
+	short int i,j;
+	if(lineid==0)
+		return;
+	for(i=0;i<MAXSIZE;i++)
+		for(j=0;j<MAXSIZE;j++)
+			if(board_beta[i][j]==-lineid)
+				board_beta[i][j]=0;
+	if(DEBUG)
+		printf("#%d     Line %d disconnected\n",attempts,lineid);
+	return;
+}
+
+
+short int avail[MAXSIZE][MAXSIZE]={}; //start=3,path=2,avail=1,nonavail=0,goal=-1
+short int goalx,goaly,goalz;
+
+
+void connect(short int lineid){ //connect line
+	short int i,j;
+	for(i=0;i<MAXSIZE;i++)
+		for(j=0;j<MAXSIZE;j++)
+			if(avail[i][j]==2){
+				if(board_beta[i][j]==0)
+					board_beta[i][j]=-lineid;
+				else{
+					printf("something wrong");
+					return;
+				}
+			}
+	if(DEBUG)
+		printf("#%d     Line %d connected\n",attempts,lineid);
+	return;
+}
+
+short int available(short int nowx,short int nowy, short int start){ //return 1 when (nowx,nowy) can be connected to goal
+	if(avail[nowy][nowx]==-1) //goal
+		return 1;
+	if(avail[nowy][nowx]!=1&&start==0)
+		return 0;
+	short int isbranch=-1;
+	if(nowx>0&&avail[nowy][nowx-1]>=2)
+		isbranch++;
+	if(nowy>0&&avail[nowy-1][nowx]>=2)
+		isbranch++;
+	if(nowx<MAXSIZE-1&&avail[nowy][nowx+1]>=2)
+		isbranch++;
+	if(nowy<MAXSIZE-1&&avail[nowy+1][nowx]>=2)
+		isbranch++;
+	if(isbranch>0){
+		avail[nowy][nowx]=1;
+		return 0;
+	}
+	if(avail[nowy][nowx]==1)
+		avail[nowy][nowx]=2;
+	short int i,src=0;
+	short int searchorder[4]; //x+-,y+-
+	/* for(i=0;i<4;i++) */
+	/* searchorder[i]=-1; */
+	if(nowx>goalx){
+		searchorder[src]=0;
+		src++;
+	}else
+		searchorder[3+src]=0;
+	if(nowy>goaly){
+		searchorder[src]=1;
+		src++;
+	}else
+		searchorder[2+src]=1;
+	if(nowx<goalx){
+		searchorder[src]=2;
+		src++;
+	}else
+		searchorder[1+src]=2;
+	searchorder[src]=3;
+	if(nowy<goaly)
+		src++;
+	/* shuffle(searchorder,0,src); */
+	/* shuffle(searchorder,src,4); */
+	/* printf("1: "); */
+	/* for(i=0;i<4;i++) */
+	/* 	printf("%d ",searchorder[i]); */
+	/* printf("\n"); */
+	short int j,t;
+	for(i=0;i<src;i++){
+		j=rand()%(src);
+		t=searchorder[i];
+		searchorder[i]=searchorder[j];
+		searchorder[j]=t;
+	}
+	for(i=src;i<4;i++){
+		j=src+rand()%(4-src);
+		t=searchorder[i];
+		searchorder[i]=searchorder[j];
+		searchorder[j]=t;
+	}
+	/* printf("2: "); */
+	/* for(i=0;i<4;i++) */
+	/* 	printf("%d ",searchorder[i]); */
+	/* printf("\n"); */
+	for(i=0;i<4;i++)
+		switch(searchorder[i]){
+			case 0:
+				if(nowx>0&&available(nowx-1,nowy,0))
+					return 1;
+				break;
+			case 1:
+				if(nowy>0&&available(nowx,nowy-1,0))
+					return 1;
+				break;
+			case 2:
+				if(nowx<MAXSIZE-1&&available(nowx+1,nowy,0))
+					return 1;
+				break;
+			case 3:
+				if(nowy<MAXSIZE-1&&available(nowx,nowy+1,0))
+					return 1;
+				break;
+			default:
+				break;
+		}
+	if(avail[nowy][nowx]==2)
+		avail[nowy][nowx]=1;
+	return 0;
+}
+
+short int connectable(short int linea,short int lineb){ //return 1 if linea can be connected when lineb is deleted
+	short int startx=-1,starty=-1,notfound=1;
+	short int i,j;
+	for(i=0;i<MAXSIZE;i++)
+		for(j=0;j<MAXSIZE;j++)
+			if(board_beta[i][j]==linea){
+				if(notfound){ //start
+					starty=i;
+					startx=j;
+					avail[i][j]=3;
+					notfound=0;
+					/* printf("1\n"); */
+				}else{ //goal
+					goaly=i;
+					goalx=j;
+					avail[i][j]=-1;
+					notfound=2;
+					/* printf("2\n"); */
+				}
+			}else if(board_beta[i][j]==0||board_beta[i][j]==-lineb||board_beta[i][j]==-linea){
+				avail[i][j]=1;
+			}else{
+				avail[i][j]=0;
+			}
+	if(startx==-1||starty==-1||notfound!=2){
+		printf("Error: Line %d\n",linea);
+		return 0;
+	}
+	return available(startx,starty,1);
+}
+
+short int try_wires(short int blockid){
+	if(block_data[blockid][2][2]==-1){ //if monomino
+		return 1;
+	}
+	if(DEBUG)
+		printf("#%d   try wire: block %d\n",attempts,blockid);
+	short int line[4],lines=0,i,j,k,found;
+	for(i=1;i<=4;i++)
+		if(block_data[blockid][i][2]>0){
+			found=0;
+			for(j=0;j<MAXSIZE&&found<=1;j++)
+				for(k=0;k<MAXSIZE&&found<=1;k++)
+					if(board_beta[j][k]==block_data[blockid][i][2])
+						found++;
+			if(found==2){
+				line[lines]=block_data[blockid][i][2];
+				printf("#%d   Block %d requires line %d\n",attempts,blockid,block_data[blockid][i][2]);
+				lines++;
+			}
+		}
+	for(i=0;i<lines;i++){
+		if(connectable(line[i],0))
+			connect(line[i]);
+		else if(i==0)
+			return 0;
+		else
+			for(j=0;j<i;j++){
+				if(connectable(line[i],line[j])){
+					erase_line(line[j]);
+					connect(line[i]);
+					if(connectable(line[j],0)){
+						connect(line[j]);
+						break;
+					}else{
+						erase_line(line[i]);
+						connect(line[j]);
+					}
+				}
+				if(j==i-1){
+					for(j=0;j<i;j++)
+						erase_line(line[j]);
+					return 0;
+				}
+			}
+	}
+	if(DEBUG){
+		printf("#%d   Block %d placed @(%d,%d)\n",attempts,blockid,block_data[blockid][0][0],block_data[blockid][0][1]);
+		print_board_beta();
+	}
 	return 1;
 }
 
@@ -188,7 +435,7 @@ void place_block(short int blockid,short int x,short int y){
 	block_data[blockid][0][1]=y;
 	if(block_data[blockid][1][2]>0){
 		board_beta[x+block_data[blockid][1][0]] [y+block_data[blockid][1][1]]=block_data[blockid][1][2];
-		add_point(blockid,block_data[blockid][1][2]);
+		update_ranks();
 	}else{
 		board_beta[x+block_data[blockid][1][0]] [y+block_data[blockid][1][1]]=SHRT_MIN;
 	}
@@ -196,27 +443,18 @@ void place_block(short int blockid,short int x,short int y){
 		for(i=2;i<=4;i++)
 			if(block_data[blockid][i][2]>0){
 				board_beta[x+block_data[blockid][i][0]] [y+block_data[blockid][i][1]]=block_data[blockid][i][2];
-				add_point(blockid,block_data[blockid][i][2]);
+				update_ranks();
 			}else{
 				board_beta[x+block_data[blockid][i][0]] [y+block_data[blockid][i][1]]=SHRT_MIN;
 			}
 	}
-	return;
-}
-
-void erase_line(short int lineid){
-	short int i,j;
-	if(lineid==0)
-		return;
-	for(i=0;i<MAXSIZE;i++)
-		for(j=0;j<MAXSIZE;j++)
-			if(board_beta[i][j]==-lineid)
-				board_beta[i][j]=0;
+	add_point(blockid);
 	return;
 }
 
 void remove_block(short int blockid){ //not for monomino
-	short int i,j;
+	if(point[blockid]<0)
+		point[blockid]=-point[blockid];
 	board_beta[block_data[blockid][0][0]+block_data[blockid][1][0]] [block_data[blockid][0][1]+block_data[blockid][1][1]]=0;
 	erase_line(block_data[blockid][1][2]);
 	if(block_data[blockid][2][2]!=-1){ //if not monomino
@@ -229,66 +467,68 @@ void remove_block(short int blockid){ //not for monomino
 	}
 	block_data[blockid][0][0]=-1;
 	block_data[blockid][0][1]=-1;
-	for(i=1;i<=blocks;i++)
-		if(i!=blockid)
-			for(j=1;j<=4;j++){
-				if(block_data[i][j][2]>0){ //if block exists
-					if(block_data[i][j][2]==block_data[blockid][1][2]){ //if edge exists
-						point[i]-=10;
-					}else if(block_data[blockid][2][2]!=-1){ //if not monomino
-						if(block_data[i][j][2]==block_data[blockid][2][2]){ //if edge exists
-							point[i]-=10;
-						}
-						if(block_data[i][j][2]==block_data[blockid][3][2]){ //if edge exists
-							point[i]-=10;
-						}
-						if(block_data[i][j][2]==block_data[blockid][4][2]){ //if edge exists
-							point[i]-=10;
-						}
-					}
-				}
-			}
-	update_ranks();
+	sub_point(blockid);
 	return;
 }
 
 short int place_and_line(short int blockid){
 	short int i,j;
+	if(DEBUG){
+		printf("#%d   RANKS (rank: block, point)\n",attempts);
+		for(i=1;i<=blocks;i++){
+			printf("      %d: %d, %d\n",i,rank[i],point[rank[i]]);
+		}
+	}
 	if(first_block==1){
 		first_block--;
 		place_block(blockid,MAXSIZE/2,MAXSIZE/2);
+		point[blockid]=-point[blockid];
+		update_ranks();
+		if(DEBUG){
+			printf("#%d   Block %d placed @(%d,%d)\n",attempts,blockid,block_data[blockid][0][0],block_data[blockid][0][1]);
+			print_board_beta();
+		}
 		return 1;
 	}
 	j=search_placable(blockid);
 	for(i=1;i<=j;i++){
+		/* printf("place: block %d\n",blockid); */
 		place_block(blockid,costrank[i][0],costrank[i][1]);
-		if(try_wire(blockid))
+		if(try_wires(blockid)){
+			point[blockid]=-point[blockid];
+			update_ranks();
 			return 1;
+		}
 		remove_block(blockid);
 	}
 	return 0;
 }
 
-void solve(void){ //solver part
-	short int i, flag, in_process=1;
+void solve(short int seed){ //solver part
+	short int i, in_process=1;
+	srand(seed);
 	while(in_process){
-		flag=1;
-		for(i=1;i<=blocks;i++)
-			if(block_data[rank[i]][0][0]<0){ //not placed
-				if(!place_and_line(rank[i])){ //if not placable
+		if(DEBUG){
+			printf("\n#%d attempt\n",attempts);
+		}
+		while(1){
+			i=rank[1];
+			if(block_data[i][0][0]<0){ //not placed
+				if(!place_and_line(i)){ //if not placable
 					point[i]+=100;
-					if(point[i]>10000){ //no answer
-						printf("Too many attempts!\n");
+					if(point[i]>10000||attempts>=100){ //no answer
+						printf("Too many trials!\n");
 						in_process=0; //end solver
 						break;
 					}
+					shuffle_random(rand());
 					reset();
 					break; //solve from beginning
 				}
-				flag=0;
+			}else
+				return;
 		}
-		if(flag)
-			break;
+		attempts++;
 	}
 	return;
 }
@@ -339,9 +579,12 @@ void translate(void){ //translate bigboard to minimal board
 }
 
 void solver(void){
+	short int seed=time(NULL); //edit here
+	/* short int seed=1; //edit here */
+	shuffle_random(seed);
 	init_points();
 	reset();
-	solve();
+	solve(seed);
 	/* shape(); */
 	/* print_board_beta(); */
 	translate();