"CF 515D" Drazil and Tiles

"CF 515D" Drazil and Tiles

The idea of a topology if it satisfies the condition '. ' There must be a 1 point before the end of the traverse (there is only one '. ' On the left and right)

When traversing to a 1-degree point u, enclose the point V with which he is connected with the corresponding parentheses, and V is also matched to zero at the same time the rest of the point in the V-in minus 1 is continuously traversed know to traverse all '. '
If it can be traversed, then the condition is not solved or many solutions are satisfied.
(Spit out the original use of pure topological thinking is also absolutely to T's. Later changed BFS

The code is as follows:

#include <iostream>#include <cstdio>#include <cstdlib>#include <queue>using namespace STD;typedef structpoint{intx, y;} Point; Point pt[4000000];intin[2002][2002];Charmp[2002][2002];intDirx[] = {0,0,1,-1};intDiry[] = {1,-1,0,0};CharCh[] ="><v^";CharSt[] ="<>^v";intM,n;intTpBOOLIinintXintY) {returnX >0&& x <= m && y >0&& y <= N;}voidRushintXintY) {inti,xx,yy,cnt =0; for(i =0; I <4;        ++i) {xx = x+dirx[i]; yy = Y+diry[i];if(Iin (XX,YY) && mp[xx][yy] = ='. ') cnt++; } In[x][y] = cnt;}BOOLTopo () {inti,j,k,x,y,xx,yy,xxx,yyy,cnt =0; queue <pair<int,int>> q; for(j =0; J <tp;        ++J) {x = pt[j].x; y = pt[j].y;if(In[x][y] = =1) {Q.push (pair<int,int> (x, y)); In[x][y] =0; }} Pair <int,int> P; while(!q.empty ())        {p = Q.front ();        Q.pop ();        x = P.first;        y = P.second; in[x][y]--; for(j =0; J <4;            ++J) {xx = x+dirx[j]; yy = Y+diry[j];if(Iin (XX,YY) && mp[xx][yy] = ='. ') {In[xx][yy] =0;                MP[XX][YY] = Ch[j]; Mp[x][y] = St[j]; for(k =0; K <4;                    ++k) {xxx = xx+dirx[k]; YYY = Yy+diry[k];if(Iin (XXX,YYY) && mp[xxx][yyy] = ='. ') {Rush (xxx,yyy);if(IN[XXX][YYY] = =1) Q.push (pair<int,int> (xxx,yyy)); }} cnt+=2; }        }    }returnCNT = = TP;}intMain () {intI,j;scanf("%d%d", &m,&n); TP =0; for(i =1; I <= m; ++i) {scanf('%s ', mp[i]+1); for(j =1; J <= N; ++J)if(Mp[i][j] = ='. ') {pt[tp].x = i;                Pt[tp++].y = j; IN[I][J] =0;if(Iin (i1, j) && mp[i-1][J] = ='. ') {in[i-1][j]++;                in[i][j]++; }if(Iin (i,j-1) && mp[i][j-1] =='. ') {in[i][j-1]++;                in[i][j]++; }            }    }if(Topo ()) { for(i =1; I <= m; ++i)printf("%s\n", mp[i]+1); }Else puts("Not unique");return 0;}

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"CF 515D" Drazil and Tiles