X = a0 + a1B + a2B2 + ...+ anBn. (其实是B^2。。。。这个坑人)
满足复数除法的剪枝真的是强大啊
枚举每一个ai, 然后 除复数B, 这里剪枝，判断是否可以整除，复数的除法公式自己推
/*ID: meixiny1PROG: testLANG: C++11*/#include <cstdio>#include <cstdlib>#include <iostream>#include <algorithm>#include <cstring>#include <climits>#include <string>#include <vector>#include <cmath>#include <stack>#include <queue>#include <set>#include <map>#include <sstream>#include <cctype>using namespace std;typedef long long ll;typedef pair<int ,int> pii;#define MEM(a,b) memset(a,b,sizeof a)#define CLR(a) memset(a,0,sizeof a);const int inf = 0x3f3f3f3f;const int MOD = 1e9 + 7;#define PI 3.1415926535898//#define LOCALll limit,ok;ll xr,xi,c,d;ll ans;int dfs(ll xr,ll xi,int deep){ll a ,b = xi,x,y;int check = 0;if(deep>100)return 0;if(xi==0 && xr<=limit && ((xr>=0 && deep == 0 ) || (xr>0))){ok = 1;printf("%lld",xr);return 1;}for(int i=0;i<=limit;i++){a =xr - i;x = (a*c+d*b)%ans;y = (c*b-a*d)%ans;if(x || y)continue;x=(a*c+d*b)/ans;y=(c*b-a*d)/ans;check |= dfs(x,y,deep+1);if(check){printf(",%d",i);return 1;}}return 0;}int main(){#ifdef LOCALfreopen("in.txt", "r", stdin);// freopen("out.txt","w",stdout);#endifint t;scanf("%d",&t);while(t--){ok = 0;scanf("%lld%lld%lld%lld",&xr,&xi,&c,&d);ans = c*c+d*d;if(sqrt(ans)==(ll)sqrt(ans))limit = (ll)sqrt(ans)-1;else limit = (ll)sqrt(ans);dfs(xr,xi,0);if(ok)printf("\n");else printf("The code cannot be decrypted.\n");}return 0;}
