"POJ 1753" Flip Game

"POJ 1753" Flip Game

Binary + (BFS) Brute Force enumeration

A two-character array was originally used to find traversal difficulties and flip a piece is also difficult to think of one-dimensional linear
Subscript 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
In the figure is the
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16
Preprocessing an array for flipping and then discovering that preprocessing is a tricky idea because only the black and white colors are available 1 0 tags see 1 0 Thought of of course is binary and made a linear just 16 bit binary all solve flip available binary operation ^ (XOR) on the code

#include <cstdio>#include <cstdlib>#include <cstring>#include <queue>#define INF 0x3f3f3f3fusing namespace STD;intMsintstep[65536];intdir[ +];BOOLvis[65536];intTpintGetnum (Char*STR)//Black 1 white 0{intI,x =0; for(i =1; I <= -; ++i) {x <<=1; x + = (Str[i] = =' B ')?1:0; }returnx;}//void printnum (int x)//{//int i = 1;//while (x)//    {//if (x&1) printf ("1");//Else printf ("0");//x >>= 1;//if (! ( i%4)) printf ("\ n");//++i;//    }//for (; I <=; ++i)//    {//printf ("0");//if (! ( i%4)) printf ("\ n");//    }//printf ("\ n");//}voidMemset (Char*STR,CharA) {intI,j; for(i =1; I <= -; ++i) Str[i] = A;}voidGetdir () {TP =0;Charstr[ the];intI,j; Memset (str,' W '); for(i = -; I >=1; I.) {str[i+1] = str[i+5] = str[i+2]=' W ';if(I-3>0) str[i-3] =' W '; Str[i] = str[i+4] =' B ';if(i%4) str[i+1] =' B ';if((I-1)%4) str[i-1] =' B ';if(I-4>0) str[i-4] =' B ';    dir[tp++] = getnum (str); }}voidBfs () {memset(Step,inf,sizeof(step));memset(Vis,0,sizeof(VIS)); STEP[MS] =0;intI,x,v; Queue <int>Q Q.push (MS); while(!q.empty ())        {x = Q.front ();        Q.pop (); VIS[X] =0; for(i =0; i < TP; ++i) {v = x^dir[i];if(Step[v] > step[x]+1) {Step[v] = step[x]+1;if(!vis[v])                    {Q.push (v); VIS[V] =1; }            }        }    }}intMain () {//freopen ("In.txt", "R", stdin);    Charstr[ -];intI,j,x; for(i =1; I < -; i + =4)    {scanf('%s ', str+i);    } ms = Getnum (str); Getdir ();//for (i = 0; i < TP; ++i)//Printnum (Dir[i]);    if(ms = =0|| ms = =65535)printf("0\n");Else{Bfs (); x = min (step[0],step[65535]);if(x = = INF)printf("impossible\n");Else printf("%d\n", x); }return 0;}

"POJ 1753" Flip Game