题意：三个瓶子，容量为s，n，m，且s装满饮料 s=m+n
求至少倒多少下能使得某两个瓶子装着相同多的饮料。
bfs 模拟
View Code
1 #include<stdio.h> 2 #include<string.h> 3 #include<math.h> 4 #include<queue> 5 #include<algorithm> 6 using namespace std; 7 const int maxn = 105; 8 struct node{ 9 int s,n,m,t; 10 }; 11 int s,n,m; 12 int vis[ maxn ][ maxn ][ maxn ]; 13 14 int bfs(){ 15 node now,next; 16 queue<node>q; 17 while( !q.empty() ) 18 q.pop(); 19 now.s=s,now.n=now.m=now.t=0; 20 memset( vis,0,sizeof( vis )); 21 vis[s][0][0]=1;//vis[ now ]=1; 22 q.push( now ); 23 while( !q.empty() ){ 24 now=q.front(),q.pop(); 25 if( ( now.s==now.n&&now.m==0 )||( now.s==now.m&&now.n==0 )||( now.m==now.n&&now.s==0 ) ) 26 return now.t; 27 int tmp; 28 if( now.s!=0 ){ 29 if( now.n!=n ){ 30 tmp=min( now.s,n-now.n ); 31 next=now; 32 next.t=now.t+1; 33 next.s-=tmp; 34 next.n+=tmp; 35 if( vis[next.s][next.n][next.m]==0/*vis[ next ]==0*/ ){ 36 vis[next.s][next.n][next.m]=1;//vis[ next ]=1; 37 q.push( next ); 38 } 39 } 40 if( now.m!=m ){ 41 tmp=min( now.s,m-now.m ); 42 next=now; 43 next.t=now.t+1; 44 next.s-=tmp; 45 next.m+=tmp; 46 if( vis[next.s][next.n][next.m]==0/*vis[ next ]==0*/ ){ 47 vis[next.s][next.n][next.m]=1;//vis[ next ]=1; 48 q.push( next ); 49 } 50 } 51 }// 1 to (2 or 3) 52 if( now.n!=0 ){ 53 tmp=now.n; 54 next=now; 55 next.t=now.t+1; 56 next.s+=tmp; 57 next.n=0; 58 if( vis[next.s][next.n][next.m]==0/*vis[ next ]==0*/ ){ 59 vis[next.s][next.n][next.m]=1;//vis[ next ]=1; 60 q.push( next ); 61 } 62 if( now.m!=m ){ 63 tmp=min( m-now.m,now.n ); 64 next=now; 65 next.t=now.t+1; 66 next.m+=tmp; 67 next.n-=tmp; 68 if( vis[next.s][next.n][next.m]==0/*vis[ next ]==0*/ ){ 69 vis[next.s][next.n][next.m]=1;//vis[ next ]=1; 70 q.push( next ); 71 } 72 } 73 }//2 to( 1 or 3 ) 74 if( now.m!=0 ){ 75 tmp=now.m; 76 next=now; 77 next.t=now.t+1; 78 next.m=0; 79 next.s+=tmp; 80 if( vis[next.s][next.n][next.m]==0/*vis[ next ]==0*/ ){ 81 vis[next.s][next.n][next.m]=1;//vis[ next ]=1; 82 q.push( next ); 83 } 84 if( now.n!=n ){ 85 tmp=min( n-now.n,now.m ); 86 next=now; 87 next.t=now.t+1; 88 next.n+=tmp; 89 next.m-=tmp; 90 if( vis[next.s][next.n][next.m]==0/*vis[ next ]==0*/ ){ 91 vis[next.s][next.n][next.m]=1;//vis[ next ]=1; 92 q.push( next ); 93 } 94 } 95 } 96 } 97 return -1; 98 } 99 100 int main(){ 101 while( scanf("%d%d%d",&s,&n,&m),s+n+m ){ 102 if( s%2==1 ){ 103 printf("NO\n"); 104 continue; 105 } 106 if( n==m ){ 107 printf("1\n"); 108 continue; 109 } 110 int ans=bfs(); 111 if( ans!=-1 ) 112 printf("%d\n",ans); 113 else 114 printf("NO\n"); 115 } 116 return 0; 117 }