标签: 数学

「AtCoder 138F」Coincidence

Given are integers L and R. Find the number, modulo 109+710^9+7, of pairs of integers (x,y)(LxyR)(x,y) (L≤x≤y≤R) such that the remainder when y is divided by x is equal to y[mbox]XORxy[mbox]XORx.