CF1879D. Sum of XOR Functions
题意:给定一个长度为n的数组a,由非负整数组成。计算 ∑ l = 1 n ∑ r = 1 n f ( l , r ) ∗ ( r − l + 1 ) \sum_{l=1}^{n} \sum_{r=1}^{n}f(l,r)*(r-l+1) l=1∑nr=1∑nf(l,r)∗(r−l+1)
其中 f ( l , r ) = a l ⊕ a l + 1 ⊕ a l + 2 ⊕ ⋯ ⊕ a r f(l,r) = a_l \oplus a_{l+1} \oplus a_{l+2} \oplus \cdots \oplus a_r <