Light OJ 1007

求区间欧拉函数平方和。。。

最后因为longlong 范围爆了WA 了， 0.0

#include<bits/stdc++.h>
using namespace std;
const int maxn = 5000000 + 131;
typedef unsigned long long LL;bool Com[maxn];
LL Num[maxn], Prim[maxn / 3];
int Cnt;void INIT()
{Num[1] = 1, Num[0] = 0;for(LL i = 2; i <= maxn; ++i){if(!Com[i]){Prim[Cnt++] = i;Num[i] = i-1;}for(LL j = 0; j < Cnt && i * Prim[j] < maxn; ++j){Com[i*Prim[j]] = true;if(i % Prim[j] == 0){Num[i*Prim[j]] = Num[i] * Prim[j];break;}elseNum[i*Prim[j]] = Num[i] * (Prim[j]-1);}}for(LL i = 0; i < maxn; ++i) Num[i] *= Num[i];for(LL i = 1; i < maxn; ++i) Num[i] += Num[i-1];
}int main()
{INIT();//cout << Num[maxn - 1] << endl;int t, a, b;scanf("%d",&t);for(int kase = 1; kase <= t; ++ kase){scanf("%d%d",&a,&b);a = a - 1;printf("Case %d: %llu\n",kase, Num[b]-Num[a]);}
}