！ HDU 4101 Ali and baba-game-(Bfs&dfs scan two-dimensional points)

Test instructions: The goal is to get a value of 1 of the gem, but the premise is to have a two-dimensional lattice from the outside to the gem of the path, if there is no need to choose a stone at a time to reduce its value by 1, until the stone value of 0 becomes the pathway, the premise of the choice of this stone is also a lattice outside to the Two people take turns, each time choose a stone, a starts first, asks by the input condition, who can win.

Analysis:

Game problem, the two people will surround the stone around a circle of stones to smash all the stones and then choose this lap stone, so it is to calculate this circle of stones outside the value of all the sum of the stone, plus the value of this circle of stone minus one sum, through the odd couple can judge who wins.

Implementation method: From Gem Dfs find a circle of stone enclosing it, with vis[][] array tag This includes the range of this circle of stone, and then from the outside of this ring BFS scan again.

The use of BFS and DFS is still extensive and continues to be practiced by practicing an in-depth understanding of its application .

In addition cin cout timed out = =

Code:

#include <iostream> #include <cstdio> #include <cstring> #include <queue>using namespace std; int N,m,a[1000][1000];int D[4][2]={{-1,0},{1,0},{0,-1},{0,1}};int Vis1[1000][1000],vis2[1000][1000];int ans;struct Node{int x, y;}; queue<node> q;bool dfs (int x,int y) {if (x==0| | x==n-1| | y==0| | Y==M-1) return true;for (int i=0;i<4;i++) {int Dx=x+d[i][0];int dy=y+d[i][1];if (dx>=0&&dx<n&    &dy>=0&&dy<m&&!vis1[dx][dy]) {vis1[dx][dy]=1; if (a[dx][dy]<=0) if (Dfs (Dx,dy)) return true;}} return false;} void BFs () {while (!q.empty ()) {node Tmp=q.front (), Q.pop (); for (int i=0;i<4;i++) {int Dx=tmp.x+d[i][0];int dy=tmp.y+d I [1];if (Dx>=0&&dx<n&&dy>=0&&dy<m&&!vis2[dx][dy]) {vis2[dx][dy]=1;if ( Vis1[dx][dy]) Ans+=a[dx][dy]-1;else{ans+=a[dx][dy];node Tmp2;tmp2.x=dx,tmp2.y=dy;q.push (TMP2);}}}} int main () {while (scanf ("%d%d", &n,&m)!=eof) {int sx,sy;for (int. i=0;i<n;i++) for (int j=0;j<m;j++) {scanf ( "%d ", &a[i][j]); if (a[i][j]==-1) sx=i,sy=j;} memset (vis1,0,sizeof (VIS1)), memset (vis2,0,sizeof (VIS2)), if (Dfs (Sx,sy)) printf ("Ali win\n"); else{ans=0;for (int i=0 ; i<n;i++) for (int j=0;j<m;j++) {if (!vis2[i][j]) {if (i==0| | i==n-1| | j==0| |      j==m-1) {vis2[i][j]=1;      if (!vis1[i][j]) {while (!q.empty ()) Q.pop ();      ANS+=A[I][J];      node tmp;      Tmp.x=i,tmp.y=j;      Q.push (TMP);      BFS ();      } else ans+=a[i][j]-1; }}}if (ans%2==1) printf ("Ali win\n"), Else printf ("Baba win\n");}}}

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！ HDU 4101 Ali and baba-game-(Bfs&dfs scan two-dimensional points)