Super Ugly Number
Write a program to find the nth super ugly number.
Super ugly numbers are positive numbers whose all prime factors are in the given prime list primes of size k. For example, [1, 2, 4, 7, 8, 13, 14, 16, 19, 26, 28, 32] is the sequence of the first 12 super ugly numbers given primes = [2, 7, 13, 19] of size 4.
Note:
(1) 1 is a super ugly number for any given primes.
(2) The given numbers in primes are in ascending order.
(3) 0 < k ≤ 100, 0 < n ≤ 106, 0 < primes[i] < 1000.
中文:写程序找出第n个超级丑数
说明:超级丑数具有如下特征:1是超级丑数,超级丑数可以表示为有限个指定质数的乘积
public int nthSuperUglyNumber(int n, int[] primes) {
int[] superUglyNumbers = new int[n];
superUglyNumbers[0] = 1;
int[] idxPrimes = new int[primes.length];
for (int i = 0; i < idxPrimes.length; i++) {
idxPrimes[i] = 0;
}
int counter = 1;
while (counter < n) {
int min = Integer.MAX_VALUE;
for (int i = 0; i < primes.length; i++) {
int temp = superUglyNumbers[idxPrimes[i]] * primes[i];
min = min < temp ? min : temp;
}
for (int i = 0; i < primes.length; i++) {
if (min == superUglyNumbers[idxPrimes[i]] * primes[i]) {
idxPrimes[i]++;
}
}
superUglyNumbers[counter] = min;
counter++;
}
return superUglyNumbers[n - 1];
}