洛谷 P1403 [AHOI2005]约数研究

原文链接：https://www.luogu.org/blog/Kelin/solution-p1403

洛谷 P1403 [AHOI2005]约数研究

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思路：Kelin的题解

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代码（自己的丑代码）

#include <iostream>
#include <cstdio>
int main(){
	int n;
	long long ans = 0;
	scanf("%d", &n);
	for(int i = 1; i <= n; ++i)
	{
		ans += n/i;
	}
	printf("%lld\n", ans);
	return 0;
}

以及优化后

#include <iostream>
#include <cstdio>
int main(){
	int n;
	long long ans = 0;
	scanf("%d", &n);
	for(int i = 1, j; i <= n; i = j+1)
	{
		j = n / (n/i);
		ans += (n/i) * (j-i+1);
	}
	printf("%lld\n", ans);
	return 0;
}

标签：约数,洛谷,int,P1403,long,ans,include
来源： https://blog.csdn.net/Mintind/article/details/100622449