BZOJ1968 [Ahoi2005]COMMON 约数研究

 1 //It is made by jump~
 2 #include <iostream>
 3 #include <cstdlib>
 4 #include <cstring>
 5 #include <cstdio>
 6 #include <cmath>
 7 #include <algorithm>
 8 #include <ctime>
 9 #include <vector>
10 #include <queue>
11 #include <map>
12 #include <set>
13 using namespace std;
14 typedef long long LL;
15 int n,ans;
16 
17 inline int getint()
18 {
19        int w=0,q=0; char c=getchar();
20        while((c<‘0‘ || c>‘9‘) && c!=‘-‘) c=getchar(); if(c==‘-‘) q=1,c=getchar(); 
21        while (c>=‘0‘ && c<=‘9‘) w=w*10+c-‘0‘, c=getchar(); return q ? -w : w;
22 }
23 
24 inline void work(){
25     n=getint(); for(int i=1;i<=n;i++) ans+=n/i; printf("%d",ans);
26 }
27 
28 int main()
29 {
30   work();
31   return 0;
32 }