6.5 Notes

Role in bin Python () method:
the string is converted into a binary number to an integer component, note that it is the result of a string
and a converted highest non-zero (e.g., bin (1) = '0b1' , and non '0b01'), and preceded 0b, indicates that this is a binary.
342.4 Power: the power must be 2%. 3 and == 1. NUM
46.Permutations: Construction dfs depth of the search function, the parameters of the current remaining num, and the current path element path, path + num is equivalent to the original collection nums (just set equal elements, ranging from the sequence).
47.Permutations2: firstly nums be sorted on the basis of the foregoing, recursive, if nums [i] == nums [i -1]: continue.