SRM 388(1-250pt)

题意：定义一个数为k-smooth，如果它最大的质因子不超过k。给定n和k，求不超过n的，k-smooth的数有多少个。(k <= 100, n <= 10^5)

解法：对于一个数t，判断它是不是k-smooth的，只需要2～k试除一遍即可。所以，暴力即可，O(k*n)。

tag:水题

// BEGIN CUT HERE
/*
 * Author:  plum rain
 * score :
 */
/*

 */
// END CUT HERE
#line 11 "SmoothNumbers.cpp"
#include <sstream>
#include <stdexcept>
#include <functional>
#include <iomanip>
#include <numeric>
#include <fstream>
#include <cctype>
#include <iostream>
#include <cstdio>
#include <vector>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <cstdlib>
#include <set>
#include <queue>
#include <bitset>
#include <list>
#include <string>
#include <utility>
#include <map>
#include <ctime>
#include <stack>

using namespace std;

#define clr0(x) memset(x, 0, sizeof(x))
#define clr1(x) memset(x, -1, sizeof(x))
#define pb push_back
#define sz(v) ((int)(v).size())
#define all(t) t.begin(),t.end()
#define zero(x) (((x)>0?(x):-(x))<eps)
#define out(x) cout<<#x<<":"<<(x)<<endl
#define tst(a) cout<<a<<" "
#define tst1(a) cout<<#a<<endl
#define CINBEQUICKER std::ios::sync_with_stdio(false)

typedef vector<int> vi;
typedef vector<string> vs;
typedef vector<double> vd;
typedef pair<int, int> pii;
typedef long long int64;

const double eps = 1e-8;
const double PI = atan(1.0)*4;
const int inf = 2139062143 / 2;

class SmoothNumbers
{
    public:
        int gao(int n, int k)
        {
            for (int i = k; i > 1; -- i)
                while (!(n % i)) n /= i;
            if (n <= k) return 1;
            return 0;
        }
        
        int countSmoothNumbers(int n, int k){
            int cnt = 0;
            for (int i = 1; i <= n; ++ i)
                if (gao(i, k)) ++ cnt;
            return cnt;
        }
        
// BEGIN CUT HERE
    public:
    void run_test(int Case) { if ((Case == -1) || (Case == 0)) test_case_0(); if ((Case == -1) || (Case == 1)) test_case_1(); if ((Case == -1) || (Case == 2)) test_case_2(); if ((Case == -1) || (Case == 3)) test_case_3(); if ((Case == -1) || (Case == 4)) test_case_4(); }
    //void run_test(int Case) { if ((Case == -1) || (Case == 0)) test_case_0();}
    private:
    template <typename T> string print_array(const vector<T> &V) { ostringstream os; os << "{ "; for (typename vector<T>::const_iterator iter = V.begin(); iter != V.end(); ++iter) os << '"' << *iter << "","; os << " }"; return os.str(); }
    void verify_case(int Case, const int &Expected, const int &Received) { cerr << "Test Case #" << Case << "..."; if (Expected == Received) cerr << "PASSED" << endl; else { cerr << "FAILED" << endl; cerr << "	Expected: "" << Expected << '"' << endl; cerr << "	Received: "" << Received << '"' << endl; } }
    void test_case_0() { int Arg0 = 10; int Arg1 = 3; int Arg2 = 7; verify_case(0, Arg2, countSmoothNumbers(Arg0, Arg1)); }
    void test_case_1() { int Arg0 = 10; int Arg1 = 4; int Arg2 = 7; verify_case(1, Arg2, countSmoothNumbers(Arg0, Arg1)); }
    void test_case_2() { int Arg0 = 15; int Arg1 = 3; int Arg2 = 8; verify_case(2, Arg2, countSmoothNumbers(Arg0, Arg1)); }
    void test_case_3() { int Arg0 = 5; int Arg1 = 20; int Arg2 = 5; verify_case(3, Arg2, countSmoothNumbers(Arg0, Arg1)); }
    void test_case_4() { int Arg0 = 100000; int Arg1 = 100; int Arg2 = 17442; verify_case(4, Arg2, countSmoothNumbers(Arg0, Arg1)); }

// END CUT HERE

};

// BEGIN CUT HERE
int main()
{
//    freopen( "a.out" , "w" , stdout );    
    SmoothNumbers ___test;
    ___test.run_test(-1);
       return 0;
}
// END CUT HERE