[LeetCode] Ugly Number II

Stefan is a hero! Personally, I love his first C++ solution.

class Solution {
public:
    int nthUglyNumber(int n) {
        vector<int> ugly(n, 1);
        int c2 = 2, c3 = 3, c5 = 5;
        int i2 = 0, i3 = 0, i5 = 0;
        for (int i = 1; i < n; i++) {
            int last = ugly[i] = min(c2, min(c3, c5));
            while (c2 <= last) c2 = 2 * ugly[++i2];
            while (c3 <= last) c3 = 3 * ugly[++i3];
            while (c5 <= last) c5 = 5 * ugly[++i5];
        }
        return ugly[n - 1];
    }
};

Well, refer to geeksforgeeks for more about ugly numbers!