Leetcode 264. Ugly Number II

triplebee

发布于 2018-01-12 14:32:09

6230

Write a program to find the n-th ugly number.

Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For example, 1, 2, 3, 4, 5, 6, 8, 9, 10, 12 is the sequence of the first 10 ugly numbers.

Note that 1 is typically treated as an ugly number, and n does not exceed 1690.

找到第n个丑陋数。

三个下标打表。

class Solution {
public:
    int nthUglyNumber(int n) {
        vector<int> res(1, 1);
        int i = 0, j = 0, k = 0;
        while(res.size() < n)
        {
            res.push_back(min(min(res[i] * 2, res[j] * 3), res[k] * 5));
            if(res.back() == res[i] * 2) i++;
            if(res.back() == res[j] * 3) j++;
            if(res.back() == res[k] * 5) k++;
        }
        return res.back();
    }
};

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原始发表：2017-04-15 ，如有侵权请联系 cloudcommunity@tencent.com 删除

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