原题Problem - C - Codeforces官方题解Editorial for Codeforces Round #919 (Div. 2) - Codeforces收获及反思同余推理如判断x,y两数是否可能同余并找出模数m.设相同的余数为k, xa*mk, yb*mk两式相减x-y(a-b)m,可见若要x,y同余则应使m能整除 x-y.#includebits/stdc.h using namespace std; int main(){ int t;cint; while(t--){ int n;cinn; vectorint a(n1); for(int i1;in;i) cina[i]; int ans0; for(int k1;kn;k){ if(n%k0){ int g0; for(int i1;in/k;i){ for(int jn/k;ijn;jn/k){ g__gcd(g,abs(a[ij]-a[ij-n/k])); } } if(g!1) ans; } } coutansendl; } }