UvaLive7362 Fare（欧拉函数）

题意：求1~n的素因子之和。

分析：欧拉函数

 #include<cstdio>
 #include<cstring>
 #include<cctype>
 #include<cstdlib>
 #include<cmath>
 #include<iostream>
 #include<sstream>
 #include<iterator>
 #include<algorithm>
 #include<string>
 #include<vector>
 #include<set>
 #include<map>
 #include<deque>
 #include<queue>
 #include<stack>
 #include<list>
 #define fin freopen("in.txt", "r", stdin)
 #define fout freopen("out.txt", "w", stdout)
 #define pr(x) cout << #x << " : " << x << "   "
 #define prln(x) cout << #x << " : " << x << endl
 typedef long long ll;
 typedef unsigned long long llu;
 const int INT_INF = 0x3f3f3f3f;
 const int INT_M_INF = 0x7f7f7f7f;
 const ll LL_INF = 0x3f3f3f3f3f3f3f3f;
 const ll LL_M_INF = 0x7f7f7f7f7f7f7f7f;
 const double pi = acos(-1.0);
 const double EPS = 1e-;
 const int dx[] = {, , -, };
 const int dy[] = {-, , , };
 const ll MOD = 1e9 + ;
 const int MAXN =  + ;
 const int MAXT =  + ;
 using namespace std;
 int pr[MAXN];
 int ps[MAXN];
 void init()
 {
     for(int i = ; i <= ; ++i)
     {
         int tmp1 = i;
         int tmp2 = i;
         for(int j = ; j <= i; ++j)
             if(tmp2 % j == )
             {
                 tmp1 = tmp1 / j * (j - );
                 tmp2 /= j;
                 while(!(tmp2 % j))
                     tmp2 /= j;
             }
         pr[i] = tmp1;
     }
     ps[] = ;
     for(int i = ; i <= ; ++i)
         ps[i] = ps[i - ] + pr[i];
 }
 int main()
 {
     int P;
     scanf("%d", &P);
     init();
     while(P--)
     {
         int x, n;
         scanf("%d%d", &x, &n);
         printf("%d %d\n", x, ps[n]);
     }
     return ;
 }