Leetcode:permutation Sequence

permutation Sequence
The set [,..., N] contains a total of n! Unique permutations.

By listing and labeling all of the permutations in order,we get the following sequence (ie, for n = 3):
"123"
"132"
"213"
"231"
"312"
"321"
Given N and K, return the kth permutation sequence.

Note:given n would be between 1 and 9 inclusive.

classSolution { Public:stringGetpermutation (intNintK) {intptable[Ten] = {1}; for(inti =1; I <=9; i++) {Ptable[i] = i * ptable[i-1]; }stringResult vector<char>numset{' 1 ',' 2 ',' 3 ',' 4 ',' 5 ',' 6 ',' 7 ',' 8 ',' 9 '}; while(N >0){inttemp = (K-1)/Ptable[n-1];            Result + = Numset[temp];            Numset.erase (Numset.begin () + temp); K = k-temp * Ptable[n-1];        n--; }returnResult }};/*in This program, ptable refers to permutation table and Numset refers to a set of numbers from 1 to 9. Before while loop, we need to initialize ptable and Numset, which is trivial. In and loop, we do these following things.1 calculate which number we'll use.2 remove that number from Numset.3 Recalc Ulate k.4 N--. Finally, we return result.*/

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Leetcode:permutation Sequence