Initially on a notepad only one character 'A' is present. You can perform two operations on this notepad for each step:
- Copy All: You can copy all the characters present on the notepad (partial copy is not allowed).
- Paste: You can paste the characters which are copied last time.
只能使用1.復制全部 2. 粘貼 兩種操作，復制得一定長度字符串。求最小步數。
Given a number n. You have to get exactly n 'A' on the notepad by performing the minimum number of steps permitted. Output the minimum number of steps to get n 'A'.
Example 1:
Input: 3
Output: 3
Explanation:
Initially, we have one character 'A'.
In step 1, we use Copy All operation.
In step 2, we use Paste operation to get 'AA'.
In step 3, we use Paste operation to get 'AAA'.
Note:
The n will be in the range [1, 1000].
這題不是DP， 用數學解法就行。
class Solution {
public int minSteps(int n) {
int res = 0;
while(n>1){
int d = findDivider(n);
res += d;
n /= d;
}
return res;
}
public int findDivider(int n){
for(int d=2;d<=Math.sqrt(n);d++){
if(n%d==0) return d;
}
return n;
}
}
