Center3.java

package cs.threephase;

import static cs.threephase.Util.*;
import static cs.threephase.Moves.*;
import java.util.*;


/*
			0	1
			3	2

4	5		0	1		0	1		4	5
7	6		3	2		3	2		7	6

			4	5
			7	6
*/

class Center3 {

	static char[][] ctmove = new char[35*35*12*2][20];
	static int[] pmove = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1};
	
	static byte[] prun = new byte[35*35*12*2];
	
	static int[] rl2std = {0, 9, 14, 23, 27, 28, 41, 42, 46, 55, 60, 69};
	static int[] std2rl = new int[70];
	

	int[] ud = new int[8];
	int[] rl = new int[8];
	int[] fb = new int[8];
	int parity = 0;
	
	static void init() {
		for (int i=0; i<12; i++) {
			std2rl[rl2std[i]] = i;
		}
		
		Center3 c = new Center3();
		for (int i=0; i<35*35*12*2; i++) {
			for (int m=0; m<20; m++) {
				c.setct(i);
				c.move(m);
				ctmove[i][m] = (char)c.getct();
			}
		}

		Arrays.fill(prun, (byte)-1);
		prun[0] = 0;
		int depth = 0;
		int done = 1;
		while (done != 29400) {
			for (int i=0; i<29400; i++) {
				if (prun[i] != depth) {
					continue;
				}
				for (int m=0; m<17; m++) {
					if (prun[ctmove[i][m]] == -1) {
						prun[ctmove[i][m]] = (byte)(depth+1);
						done++;
					}
				}
			}
			depth++;
			// System.out.println(String.format("%2d%10d", depth, done));
		}
	}
	
	void set(CenterCube c, int eXc_parity) {
		int parity = (c.ct[0]>c.ct[8] ^ c.ct[8]>c.ct[16] ^ c.ct[0]>c.ct[16]) ? 1 : 0;
		for (int i=0; i<8; i++) {
			ud[i] = (c.ct[i] & 1) ^ 1;
			fb[i] = (c.ct[i+8] & 1) ^ 1;
			rl[i] = (c.ct[i+16] & 1) ^ 1 ^ parity;
		}
		this.parity = parity ^ eXc_parity;
	}
	
	int getct() {
		int idx = 0;
		int r = 4;
		for (int i=6; i>=0; i--) {
			if (ud[i] != ud[7]) {
				idx += Cnk[i][r--];
			}
		}
		idx *= 35;
		r = 4;
		for (int i=6; i>=0; i--) {
			if (fb[i] != fb[7]) {
				idx += Cnk[i][r--];
			}
		}
		idx *= 12;
		int check = fb[7] ^ ud[7];
		int idxrl = 0;
		r = 4;
		for (int i=7; i>=0; i--) {
			if (rl[i] != check) {
				idxrl += Cnk[i][r--];
			}
		}
		return parity + 2 * (idx + std2rl[idxrl]);
	}
	
	void setct(int idx) {
		parity = idx & 1;
		idx >>>= 1;
		int idxrl = rl2std[idx % 12];
		idx /= 12;
		int r = 4;
		for (int i=7; i>=0; i--) {
			rl[i] = 0;
			if (idxrl >= Cnk[i][r]) {
				idxrl -= Cnk[i][r--];
				rl[i] = 1;
			}
		}		
		int idxfb = idx % 35;
		idx /= 35;
		r = 4;
		fb[7] = 0;
		for (int i=6; i>=0; i--) {
			if (idxfb >= Cnk[i][r]) {
				idxfb -= Cnk[i][r--];
				fb[i] = 1;
			} else {
				fb[i] = 0;
			}
		}
		r = 4;
		ud[7] = 0;
		for (int i=6; i>=0; i--) {
			if (idx >= Cnk[i][r]) {
				idx -= Cnk[i][r--];
				ud[i] = 1;
			} else {
				ud[i] = 0;
			}
		}
	}

	void move(int i) {
		parity ^= pmove[i];
		switch (i) {
		case 0:		//U
		case 1:		//U2
		case 2:		//U'	
			swap(ud, 0, 1, 2, 3, i%3);
			break;
		case 3:		//R2
			swap(rl, 0, 1, 2, 3, 1);
			break;
		case 4:		//F
		case 5:		//F2
		case 6:		//F'
			swap(fb, 0, 1, 2, 3, (i-1)%3);
			break;
		case 7:		//D
		case 8:		//D2
		case 9:		//D'
			swap(ud, 4, 5, 6, 7, (i-1)%3);
			break;
		case 10:	//L2
			swap(rl, 4, 5, 6, 7, 1);
			break;
		case 11:	//B
		case 12:	//B2
		case 13:	//B'
			swap(fb, 4, 5, 6, 7, (i+1)%3);
			break;
		case 14:	//u2
			swap(ud, 0, 1, 2, 3, 1);
			swap(rl, 0, 5, 4, 1, 1);
			swap(fb, 0, 5, 4, 1, 1);
			break;
		case 15:	//r2
			swap(rl, 0, 1, 2, 3, 1);
			swap(fb, 1, 4, 7, 2, 1);
			swap(ud, 1, 6, 5, 2, 1);
			break;
		case 16:	//f2
			swap(fb, 0, 1, 2, 3, 1);
			swap(ud, 3, 2, 5, 4, 1);
			swap(rl, 0, 3, 6, 5, 1);
			break;
		case 17:	//d2
			swap(ud, 4, 5, 6, 7, 1);
			swap(rl, 3, 2, 7, 6, 1);
			swap(fb, 3, 2, 7, 6, 1);
			break;
		case 18:	//l2
			swap(rl, 4, 5, 6, 7, 1);
			swap(fb, 0, 3, 6, 5, 1);
			swap(ud, 0, 3, 4, 7, 1);
			break;
		case 19:	//b2
			swap(fb, 4, 5, 6, 7, 1);
			swap(ud, 0, 7, 6, 1, 1);
			swap(rl, 1, 4, 7, 2, 1);
			break;		
		}
	}
}