UVA 1533 (bfs+ State compression)

Test instructions: There is a chessboard as follows, black means a pawn, white means empty, the initial state of the board is a position n is empty, and other positions have pieces.

Each time you can select a piece in a straight line or a continuous number of pieces to jump to a blank position, and then this one or more pieces are taken away, ask at least a few steps to the board to take the pieces to the left one and the same position and the initial blank position. Outputs the starting and Lazi positions of several steps and each step. The solution of the output dictionary order is minimal, and the output impossible is not solved.

Puzzle: Because there are 15 positions on the board, you can use state compression to indicate the state of the Board, 1 for a pawn, 0 for a blank, and 6 for each pawn, so use a flag[i][j] array to indicate where I walk in the direction J, then BFS, change the checkerboard state with XOR or operation.

#include <stdio.h> #include <string.h> #include <queue>using namespace std;const int N = 15; int POS, mp[1 << n];int flag[15][6] = {{ -1,-1,-1,-1,2,3},{-1,1,-1,3,4,5},{1,-1,2,-1,5,6}, { -1,2,-1,5,7,8},{ 2,3,4,6,8,9},{3,-1,5,-1,9,10}, { -1,4,-1,8,11,12},{4,5,7,9,12,13},{5,6,8,10,13,14}, {6,-1,9,-1,14,15},{-1,7,-1,12 , -1,-1},{7,8,11,13,-1,-1}, {8,9,12,14,-1,-1},{9,10,13,15,-1,-1},{10,-1,14,-1,-1,-1}};struct P {int Step;intpath[N + 5][2];int s;int num;}; int BFS (int s) {queue<p> q;while (!q.empty ()) Q.pop ();  P A;A.S = s;a.num = 1;a.step = 0;q.push (a), while (!q.empty ()) {P u = Q.front (), Q.pop (), for (int i = 0; i <; i++) {if (U.S. & (1 << i)) {for (int j = 0; J < 6; J + +) {int cur = i;  P B = u;if (flag[i][j]! =-1 && b.s & (1 << (Flag[i][j]-1)) {while (cur! =-1 && b.s & (1 << cur) {b.s ^= (1 << cur); cur = flag[cur][j]-1;b.num++;} if (cur < 0) continue;b.s |= (1 << cur); b.step = U.step + 1;b.path[b.stEp][0] = i;b.path[b.step][1] = cur;b.num--;if (!mp[b.s]) {if (B.num = = && B.s & (1 << (pos-1))) {PR INTF ("%d\n%d%d", B.step, B.path[1][0] + 1, b.path[1][1] + 1); for (int k = 2; k <= b.step; k++) printf ("%d%d", b.path[ K][0] + 1, b.path[k][1] + 1);p rintf ("\ n"); return 1;} MP[B.S] = 1;q.push (b);}}}}} return 0;}  int main () {int t;scanf ("%d", &t), while (t--) {scanf ("%d", &pos), memset (MP, 0, sizeof (MP)); int temp = (1 << 1) ^ (1 << (pos-1)), mp[temp] = 1;int res = BFS (temp), if (!res) printf ("impossible\n");} return 0;}

UVA 1533 (bfs+ State compression)