题目链接：http://poj.org/problem?id=3126
每次四种决策，千位||百位||十位||个位。
其实各位数字不用存进结构体里，每次算一下就好
1 #include<cstdio> 2 #include<queue> 3 #include<cstring> 4 using namespace std; 5 int c[10]={0,1,2,3,4,5,6,7,8,9}; 6 int vis[10000]; 7 int ispri[10000]; 8 struct node 9 { 10 int oo[4]; 11 int d; 12 int x; 13 }now,nex; 14 int x,y; 15 void trans(int* a,int x) 16 { 17 int i=3; 18 while(x) 19 { 20 a[i--]=x%10; 21 x/=10; 22 } 23 } 24 void is() 25 { 26 for(int i=2;i*i<10010;i++) if(!ispri(i)) 27 for(int j=i*i;j<10010;j+=i) 28 ispri[j]=1; 29 } 30 int bfs() 31 { 32 queue<node> q; 33 trans(now.oo,x); 34 now.x=x; 35 now.d=0; 36 q.push(now); 37 vis[x]=1; 38 while(!q.empty()) 39 { 40 now=q.front(); 41 q.pop(); 42 if(now.x==y) return now.d; 43 for(int i=1;i<10;i++) 44 { 45 if(c[i]!=now.oo[0]) //千位 46 { 47 nex.x=c[i]*1000+now.x%1000; 48 if(!vis[nex.x]&&!ispri[nex.x]) 49 { 50 vis[nex.x]=1; 51 trans(nex.oo,nex.x); 52 nex.d=now.d+1; 53 q.push(nex); 54 } 55 } 56 } 57 for(int i=0;i<10;i++) //百位 58 { 59 if(c[i]!=now.oo[1]) 60 { 61 nex.x=c[i]*100+now.x/1000*1000+now.x%100; 62 if(!vis[nex.x]&&!ispri[nex.x]) 63 { 64 vis[nex.x]=1; 65 trans(nex.oo,nex.x); 66 nex.d=now.d+1; 67 q.push(nex); 68 } 69 } 70 } 71 for(int i=0;i<10;i++) //十位 72 { 73 if(c[i]!=now.oo[2]) 74 { 75 nex.x=c[i]*10+now.x/100*100+now.x%10; 76 if(!vis[nex.x]&&!ispri[nex.x]) 77 { 78 vis[nex.x]=1; 79 trans(nex.oo,nex.x); 80 nex.d=now.d+1; 81 q.push(nex); 82 } 83 } 84 } 85 for(int i=0;i<10;i++) //个位 86 { 87 if(c[i]!=now.oo[3]) 88 { 89 nex.x=c[i]+now.x/10*10; 90 if(!vis[nex.x]&&!ispri[nex.x]) 91 { 92 vis[nex.x]=1; 93 trans(nex.oo,nex.x); 94 nex.d=now.d+1; 95 q.push(nex); 96 } 97 } 98 } 99 } 100 101 } 102 103 int main() 104 { 105 int t; 106 scanf("%d",&t); 107 memset(ispri,0,sizeof(ispri)); 108 is(); 109 while(t--) 110 { 111 memset(vis,0,sizeof(vis)); 112 scanf("%d%d",&x,&y); 113 printf("%d ",bfs()); 114 } 115 }