题解 | #丑数#
丑数
http://www.nowcoder.com/practice/6aa9e04fc3794f68acf8778237ba065b
三指针方法
import java.util.*;
// 时间O(N)空间O(N)
public class Solution {
public int GetUglyNumber_Solution(int index) {
// 1 2 3 4 5 6
if(index <= 6) return index;
int i2 = 0,i3 = 0,i5 = 0;
int[] res = new int[index];
res[0] = 1;
for(int i=1;i<index;i++){
res[i] = Math.min(res[i2]*2,Math.min(res[i3]*3,res[i5]*5));
if(res[i] == res[i2]*2) i2++;
if(res[i] == res[i3]*3) i3++;
if(res[i] == res[i5]*5) i5++;
}
return res[index-1];
}
}
查看20道真题和解析