<qiyuangong>024_Swap_Nodes_in_Pairs_1.py
def swapPairs( head):
    current = last = last2 = head
    while current is not None:
        nex = current.next
        if current == last.next:
            last.next = nex
            current.next = last
            if last == head:
                head = current
            else:
                last2.next = current
            last2 = last
            last = nex
        current = nex
    return head
def sample_funcname ( var_0 ) :
    var_3 = var_1 = var_2 = var_0
    while var_3 is not None :
        var_6 = var_3.next
        if var_3 == var_1.next :
            var_1.next = var_6
            var_3.next = var_1
            if var_1 == var_0 :
                var_0 = var_3
            else :
                var_2.next = var_3
            var_2 = var_1
            var_1 = var_6
        var_3 = var_6
    return var_0
