Bi-shoe and Phi-shoe LightOJ - 1370(尤拉函式)
Bamboo Pole-vault is a massively popular sport in Xzhiland. And Master Phi-shoe is a very popular coach for his success. He needs some bamboos for his students, so he asked his assistant Bi-Shoe to go to the market and buy them. Plenty of Bamboos of all possible integer lengths (yes!) are available in the market. According to Xzhila tradition,
Score of a bamboo =Φ (bamboo's length)
(Xzhilans are really fond of number theory). For your information,Φ (n)= numbers less thannwhich are relatively prime (having no common divisor other than 1) ton. So, score of a bamboo of length 9 is 6 as 1, 2, 4, 5, 7, 8 are relatively prime to 9.
The assistant Bi-shoe has to buy one bamboo for each student. As a twist, each pole-vault student of Phi-shoe has a lucky number. Bi-shoe wants to buy bamboos such that each of them gets a bamboo with a score greater than or equal to his/her lucky number. Bi-shoe wants to minimize the total amount of money spent for buying the bamboos. One unit of bamboo costs 1 Xukha. Help him.
Input
Input starts with an integerT (≤ 100), denoting the number of test cases.
Each case starts with a line containing an integern (1 ≤ n ≤ 10000)denoting the number of students of Phi-shoe. The next line containsnspace separated integers denoting the lucky numbers for the students. Each lucky number will lie in the range[1, 106
Output
For each case, print the case number and the minimum possible money spent for buying the bamboos. See the samples for details.
Sample Input
3
5
1 2 3 4 5
6
10 11 12 13 14 15
2
1 1
Sample Output
Case 1: 22 Xukha
Case 2: 88 Xukha
Case 3: 4 Xukha
題意:
給出 n 個數字的序列 a[n] , 對於每個數字ai 找到一個數字 bi 使得 bi的尤拉函式值大於等於 a ,求滿足條件的 bi 的和的最小值sum.
思路:尤拉函式打表後對於每個a 從 a+1 開始遍歷,尋找滿足條件的最小的b求和即可。
程式碼;
#include <set> #include <map> #include <list> #include <stack> #include <queue> #include <deque> #include <cmath> #include <string> #include <vector> #include <cstdio> #include <cstring> #include <cstdlib> #include <sstream> #include <iostream> #include <algorithm> #include <unordered_map> #define INF 0x3f3f3f3f #define ll long long #define ull unsigned long long #define fcio ios::sync_with_stdio(false); cin.tie(0); cout.tie(0) using namespace std; const int maxn=1e6+10; int euler[maxn]; void dbeuler(void) { for(int i=0;i<maxn;i++) euler[i]=i; for(int i=2;i<maxn;i++) { if(euler[i]==i) { for(int j=i;j<maxn;j+=i) euler[j]=euler[j]/i*(i-1); } } } int main() { dbeuler(); int n; int t; cin>>t; for(int k=1;k<=t;k++) { cin>>n; ll sum=0; for(int i=0;i<n;i++) { int a; cin>>a; for(int j=a+1;j<maxn;j++) { if(euler[j]>=a) { sum+=j; break; } } } cout<<"Case "<<k<<": "<<sum<<" Xukha"<<endl; } }