几天前找人内推，普通的sde, 收到OA还是老题，地里都有，算简单，就不贴图了
1， debug， most frequent characters, 返回最多的字母earliest alphabet
2，skyline， paint，用了stack解决
3， factorial(N)/factorial(K)*factorial(N-K), 要求efficient，花了点时间做优化
帖一下Gamble这题
When John gambles at the casino, he always uses a special system of tactics that he devised himself. It’s based on always betting in one of two ways in each game:
• betting exactly one chip (to test his luck);
• betting all-in (he bets everything he has).
Wins in the casino are paid equal to the wager, so if he bets C chips and wins, he gets 2C chips back. If he loses, he doesn’t get any chips back.
It was a very lucky day yesterday and John won every game he played, starting with one chip and leaving the casino with N chips. We also know that John played all-in no more than K times. Your task is to calculate the smallest possible number of rounds he could have played.
Note: betting just one chip is never considered playing all-in.
Write a function:
class Solution { public int solution(int N, int K); }
that, given an integer N and an integer K, returns the minimum number of rounds that are necessary for John to leave the casino with N chips, having played all-in no more than K times.
Given N = 8 and K = 0, the answer is 7 . K is 0 so John bets 1 chip in each round. The number of chips were as follows:
at the beginning: 1
after the 1st round: 2 (he bet 1)
after the 2nd round: 3 (he bet 1)
after the 3rd round: 4 (he bet 1)
after the 4th round: 5 (he bet 1)
after the 5th round: 6 (he bet 1)
after the 6th round: 7 (he bet 1)
after the 7th round: 8 (he bet 1)
he played all-in 0 times
Given N =18 and K = 2, the answer is 6 . The shortest game would be:
at the beginning: 1
after the 1st round: 2 (he bet 1)
after the 2nd round: 3 (he bet 1)
after the 3rd round: 4 (he bet 1)
after the 4th round: 8 (all-in)
after the 5th round: 9 (he bet 1)
after the 6th round: 18 (all-in)
he played all-in 2 times
Given N = 10 and K = 10, the answer is 4 . The shortest game would be:
at the beginning: 1
after the 1st round: 2 (he bet 1)
after the 2nd round: 4 (all-in)
after the 3rd round: 5 (he bet 1)
after the 4th round: 10 (all-in)
he played all-in 2 times
Write an efficient algorithm for the following assumptions:
• N is an integer within the range [1…2,147,483,647];
• K is an integer within the range [0…100].