Uva1602-lattice Animals

Enter N,w,h (1<=n<=10,1<=w,h<=n) to find the number of different n-connected blocks in the w*h grid.

Backtracking solution, first determine the search object, lattice connectivity, so the connected block as a search object, each enumeration of a location, and then put a new block, and finally a heavy sentence.

Each block is enumerated many times, and there is a way to ensure that each N-block is enumerated exactly once.

Enumerate each case with the function generate ().

#include <cstdio> #include <cstring> #include <algorithm> #include <set>using namespace std;    struct cell{int x, y;    Cell (int x=0,int y=0): X (x), Y (y) {}; BOOL operator < (const cell& RHS) Const {return x < rhs.x| |    (X==RHS.X&AMP;&AMP;Y&LT;RHS.Y); }};typedef set<cell> Polyomino; #define For_cell (C,p) for (Polyomino::const_iterator c= (P). Begin (); c!= (P). End ()    ; ++c) inline Polyomino normalize (const Polyomino &p) {int minx=p.begin ()->x, miny = P.begin ()->y;        For_cell (c,p) {MinX = min (MinX, c->x);    miny = min (miny, c->y);    } Polyomino p2;    For_cell (c,p) P2.insert (CELL (c->x-minx,c->y-miny)); return p2;}    Inline Polyomino Rotate (const Polyomino &p) {polyomino P2;    For_cell (c,p) P2.insert (CELL (c->y,-c->x)); Return normalize (p2);}    Inline Polyomino Flip (const polyomino&p) {Polyomino P2;    For_cell (c,p) P2.insert (CELL (c->x,-c->y)); Return normalize (p2);} const INT dx[]={-1,1,0,0};const int dy[]={0,0,-1,1};const int maxn=10;set<polyomino> poly[maxn+1];int ans[maxn+1][maxn+1 ][maxn+1];///add a cell to p0 ans check whether it's new if So,add to the Polyonimo setvoid Check_polyomino (const Polyomi    no& P0, const cell& c) {Polyomino p = p0;    P.insert (c);    P=normalize (P);    int n=p.size ();        for (int i=0;i<4;i++) {if (Poly[n].count (p)!=0) return;    P=rotate (P);    } p=flip (P);        for (int i=0;i<4;i++) {if (Poly[n].count (p)!=0) return;    P=rotate (P); } poly[n].insert (P);}    void Generate () {Polyomino s;    S.insert (Cell (0,0));    Poly[1].insert (s); Generate for (int. n=2;n<=maxn;n++) {for (Set<polyomino>::iterator p=poly[n-1].begin ();p!=poly[n-1].end (); ++p) For_cell (c,*p) for (int dir=0;dir<4;dir++) {CELL News (C->x+dx[dir],c-&gt                ; Y+dy[dir]);            if (P->count (News) ==0) Check_polyomino (*p,news); }}///precOmpute answers for (int n=1;n<=maxn;n++) for (int. w=1;w<=maxn;w++) for (int. h=1;h<=maxn;h++) {in        T cnt=0;            For (Set<polyomino>::iterator p=poly[n].begin ();p!=poly[n].end (); ++p) {int maxx=0,maxy=0;                For_cell (c,*p) {Maxx=max (maxx,c->x);            Maxy=max (Maxy,c->y);        } if (min (maxx,maxy) <min (h,w) &&max (maxx,maxy) <max (h,w)) ++cnt;    } ans[n][w][h]=cnt;    }}int Main () {Generate ();    int n,w,h;    while (scanf ("%d%d%d", &n,&w,&h) ==3) {printf ("%d\n", Ans[n][w][h]); } return 0;}

Uva1602-lattice Animals