leetcode【507】Perfect

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leetcode【507】Perfect

写在最前面:刷点简单的题水一水

leetcode【507】Perfect Number

We define the Perfect Number is a positive integer that is equal to the sum of all its positive divisors except itself.

Now, given an integer n, write a function that returns true when it is a perfect number and false when it is not.

Example:

Input: 28
Output: True
Explanation: 28 = 1 + 2 + 4 + 7 + 14

Note: The input number n will not exceed 100,000,000. (1e8)

题目很简单,没啥好说的,求下该数的因子,把自己去掉即可

import math


class Solution:
    def checkPerfectNumber(self, num):
        """
        :type num: int
        :rtype: bool
        """
        if num <= 1:
            return False
        rlist = []
        i = 1
        newnum = 0
        while i <= math.sqrt(num):
            if num % i == 0:
                a = num // i
                rlist.append(i)
                if (a != num) & (a != i):
                    rlist.append(a)
            i += 1
        for j in range(len(rlist)):
            newnum += rlist[j]
        if num == newnum:
            return True
        else:
            return False

放一段java的,思路是一样的,具体细节你想怎么写就怎么写,从0开始算,还是从1开始,无所谓

class Solution {
    public boolean checkPerfectNumber(int num) {
        if(num <=1)
            return false;
    int sum = 0;
    int top = (int) Math.sqrt(num);
    for(int i = 1;i <= top; i++) {
        if((num % i) ==0) {
            sum += i;
            if ((num / i) != i && (num / i) !=num)
                {sum += num /i;}
            }
        }
    return sum == num;

    }   
}
public class Solution {
    public boolean checkPerfectNumber(int num) {
        if(num <= 1) 
            return false;
        int sum = 1;
        int up = (int)Math.sqrt(num);
        for(int i = 2; i <= up; i++){
            if((num % i) == 0) {sum += i; sum += num / i;}
        }

        return sum == num;
    }
}

python和java来回切有时候会反应不过来...不过都是本地和leetcode调试通过的,下面放一个本地的测试代码:

package Arithmetic;

public class checkPerfectNumber {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        checkPerfectNumber check = new checkPerfectNumber();
        check.checkPerfectNumber(28);
        System.out.println(check.checkPerfectNumber(28));
    }
    public boolean checkPerfectNumber(int num) {
        if(num <=1)
            return false;
    int sum = 0;
    int top = (int) Math.sqrt(num);
    for(int i = 1;i <= top; i++) {
        if((num % i) ==0) {
            sum += i;
            if ((num / i) != i && (num / i) !=num)
                {sum += num /i;}
            }
        }
    System.out.println(sum);
    return sum == num;

    } 

}
    ArithmeticJia         2         1284         Leetcode         34    

David Ramon

ArithmeticJia

www.guanacossj.com

Life is Short,You need Python

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