A 考虑\(x + 1 = \sqrt{d}\)时在有理域上有最优界. 那我在整数域上附近取三个点取min就行了. // code by fhq_treap #include<bits/stdc++.h> #define ll long long #define N 300005 inline ll read(){ char C=getchar(); ll A=0 , F=1; while(('0' > C || C > '9') && (C != '-')) C=…