A pair of numbers has a unique LCM but a single number can be the LCM of more than one possible
pairs. For example 12 is the LCM of (1, 12), (2, 12), (3,4) etc. For a given positive integer N, the
number of different integer pairs with LCM is equal to N can be called the LCM cardinality of that
number N. In this problem your job is to find out the LCM cardinality of a number.
Input
The input file contains at most 101 lines of inputs. Each line contains an integer N (0 < N ≤ 2 ∗ 109
).
Input is terminated by a line containing a single zero. This line should not be processed.
Output
For each line of input except the last one produce one line of output. This line contains two integers
N and C. Here N is the input number and C is its cardinality. These two numbers are separated by a
single space.
Sample Input
2
12
24
101101291
0
Sample Output
2 2
12 8
24 11
101101291 5
题意:给出一个序列,要求将所有可能的序列每个序列形成的数值相加的和。
题解:计算每个位置上可能放的数是哪些,计算对答案的贡献的一种,利用到了组合数学,可以类似求杨辉三角去求组合数
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
//meek///#include<bits/stdc++.h> #include <cstdio> #include <cmath> #include <cstring> #include <algorithm> #include<iostream> #include<bitset> #include<map> using namespace std ; #define mem(a) memset(a,0,sizeof(a)) #define pb push_back #define fi first #define se second #define MP make_pair typedef long long ll; const int N = 20; const int M = 1000001; const int inf = 0x3f3f3f3f; const int MOD = 1000000007; const double eps = 0.000001; ll ans,c[N][N]; int a[N],v[N],n; ll add(){ int k = n-1; ll t = 1; for(int i=0;i<10;i++) { t *= c[k][v[i]]; k -= v[i]; } return t; } int main() { for(int i=0;i<=12;i++) { c[i][0] = 1; for(int j=1;j<=i;j++) c[i][j] = c[i-1][j-1] + c[i-1][j]; } while(~scanf("%d",&n)) { if(n==0)break; mem(v);ans = 0; ll sum = 0; for(int i=1;i<=n;i++) scanf("%d",&a[i]),v[a[i]]++; for(ll i=0;i<=9;i++) { if(v[i]) { v[i]--; ll tmp = add(); v[i]++; sum += i*tmp; } } ans = 0; for(int i=1;i<=n;i++) ans = ans*10 + sum; printf("%lld ",ans); } return 0; }