https://vjudge.net/contest/259447#problem/E
bfs，k个限制条件以数组的额外k维呈现。
1 #include <bits/stdc++.h> 2 using namespace std; 3 #define ll long long 4 #define minv 1e-6 5 #define inf 1e9 6 #define pi 3.1415926536 7 #define nl 2.7182818284 8 const ll mod=1e9+7;//998244353 9 const int maxn=1e5+10; 10 11 int qx[maxn*100],qy[maxn*100],num[maxn*100],step[maxn*100],ci[maxn],c[5]={1,10,100,1000,10000},d[5]; 12 bool vis[maxn][4][3]; 13 14 int main() 15 { 16 int head,tail,i,j,s,x,y,ss,bu; 17 head=0,tail=1; 18 for (i=0;i<1e5;i++) 19 ci[i]=inf; 20 qx[1]=3,qy[1]=2,num[1]=12345,step[1]=0,ci[12345]=0,vis[12345][3][2]=1; 21 while (head<tail) 22 { 23 head++; 24 s=num[head]; 25 x=qx[head]; 26 y=qy[head]; 27 bu=step[head]+1; 28 ss=s; 29 for (i=0;i<5;i++) 30 d[i]=ss%10,ss/=10; 31 for (i=0;i<4;i++) 32 { 33 j=i+1; 34 ss=s+(c[i]-c[j])*(d[j]-d[i]); 35 if (!vis[ss][x][y]) 36 { 37 tail++; 38 qx[tail]=x; 39 qy[tail]=y; 40 num[tail]=ss; 41 step[tail]=bu; 42 ci[ss]=min(ci[ss],bu); 43 vis[ss][x][y]=1; 44 } 45 } 46 if (x!=0) 47 for (i=0;i<5;i++) 48 { 49 ss=s+c[i]*(d[i]==9?-9:1); 50 if (!vis[ss][x-1][y]) 51 { 52 tail++; 53 qx[tail]=x-1; 54 qy[tail]=y; 55 num[tail]=ss; 56 step[tail]=bu; 57 ci[ss]=min(ci[ss],bu); 58 vis[ss][x-1][y]=1; 59 } 60 } 61 if (y!=0) 62 for (i=0;i<5;i++) 63 { 64 ss=s+c[i]*(d[i]*2%10-d[i]); 65 if (!vis[ss][x][y-1]) 66 { 67 tail++; 68 qx[tail]=x; 69 qy[tail]=y-1; 70 num[tail]=ss; 71 step[tail]=bu; 72 ci[ss]=min(ci[ss],bu); 73 vis[ss][x][y-1]=1; 74 } 75 } 76 } 77 while (~scanf("%d",&s)) 78 printf("%d ",ci[s]==inf?-1:ci[s]); 79 return 0; 80 }