You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

34 lines
794 B

This file contains ambiguous Unicode characters!

This file contains ambiguous Unicode characters that may be confused with others in your current locale. If your use case is intentional and legitimate, you can safely ignore this warning. Use the Escape button to highlight these characters.

package class48;
public class Problem_0483_SmallestGoodBase {
// ""4651" -> 4651
public static String smallestGoodBase(String n) {
long num = Long.valueOf(n);
// n这个数需要从m位开始试固定位数一定要有m位
for (int m = (int) (Math.log(num + 1) / Math.log(2)); m > 2; m--) {
// num开m次方
long l = (long) (Math.pow(num, 1.0 / m));
long r = (long) (Math.pow(num, 1.0 / (m - 1))) + 1L;
while (l <= r) {
long k = l + ((r - l) >> 1);
long sum = 0L;
long base = 1L;
for (int i = 0; i < m && sum <= num; i++) {
sum += base;
base *= k;
}
if (sum < num) {
l = k + 1;
} else if (sum > num) {
r = k - 1;
} else {
return String.valueOf(k);
}
}
}
return String.valueOf(num - 1);
}
}