T 1 T_1 T1
S o l u t i o n : Solution: Solution: ( ∑ i = 1 m p r e [ i − 1 ] ∩ s u f [ i + 1 ] ) − ( n − 1 ) ∩ a l l (\sum_{i=1}^{m}{pre[i-1] \cap suf[i+1]}) -(n-1)\cap all (∑i=1mpre[i−1]∩suf[i+1])−(n−1)∩all
T 2 T_2 T2
S o l u t i o n : Solution: Solution:
T 3 T_3 T3