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

  1 // BEGIN CUT HERE
  2 /*
  3  * Author:  plum rain
  4  * score :
  5  */
  6 /*
  7 
  8  */
  9 // END CUT HERE
 10 #line 11 "SmoothNumbers.cpp"
 11 #include <sstream>
 12 #include <stdexcept>
 13 #include <functional>
 14 #include <iomanip>
 15 #include <numeric>
 16 #include <fstream>
 17 #include <cctype>
 18 #include <iostream>
 19 #include <cstdio>
 20 #include <vector>
 21 #include <cstring>
 22 #include <cmath>
 23 #include <algorithm>
 24 #include <cstdlib>
 25 #include <set>
 26 #include <queue>
 27 #include <bitset>
 28 #include <list>
 29 #include <string>
 30 #include <utility>
 31 #include <map>
 32 #include <ctime>
 33 #include <stack>
 34 
 35 using namespace std;
 36 
 37 #define clr0(x) memset(x, 0, sizeof(x))
 38 #define clr1(x) memset(x, -1, sizeof(x))
 39 #define pb push_back
 40 #define sz(v) ((int)(v).size())
 41 #define all(t) t.begin(),t.end()
 42 #define zero(x) (((x)>0?(x):-(x))<eps)
 43 #define out(x) cout<<#x<<":"<<(x)<<endl
 44 #define tst(a) cout<<a<<" "
 45 #define tst1(a) cout<<#a<<endl
 46 #define CINBEQUICKER std::ios::sync_with_stdio(false)
 47 
 48 typedef vector<int> vi;
 49 typedef vector<string> vs;
 50 typedef vector<double> vd;
 51 typedef pair<int, int> pii;
 52 typedef long long int64;
 53 
 54 const double eps = 1e-8;
 55 const double PI = atan(1.0)*4;
 56 const int inf = 2139062143 / 2;
 57 
 58 class SmoothNumbers
 59 {
 60     public:
 61         int gao(int n, int k)
 62         {
 63             for (int i = k; i > 1; -- i)
 64                 while (!(n % i)) n /= i;
 65             if (n <= k) return 1;
 66             return 0;
 67         }
 68         
 69         int countSmoothNumbers(int n, int k){
 70             int cnt = 0;
 71             for (int i = 1; i <= n; ++ i)
 72                 if (gao(i, k)) ++ cnt;
 73             return cnt;
 74         }
 75         
 76 // BEGIN CUT HERE
 77     public:
 78     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(); }
 79     //void run_test(int Case) { if ((Case == -1) || (Case == 0)) test_case_0();}
 80     private:
 81     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(); }
 82     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 << "\tExpected: \"" << Expected << '\"' << endl; cerr << "\tReceived: \"" << Received << '\"' << endl; } }
 83     void test_case_0() { int Arg0 = 10; int Arg1 = 3; int Arg2 = 7; verify_case(0, Arg2, countSmoothNumbers(Arg0, Arg1)); }
 84     void test_case_1() { int Arg0 = 10; int Arg1 = 4; int Arg2 = 7; verify_case(1, Arg2, countSmoothNumbers(Arg0, Arg1)); }
 85     void test_case_2() { int Arg0 = 15; int Arg1 = 3; int Arg2 = 8; verify_case(2, Arg2, countSmoothNumbers(Arg0, Arg1)); }
 86     void test_case_3() { int Arg0 = 5; int Arg1 = 20; int Arg2 = 5; verify_case(3, Arg2, countSmoothNumbers(Arg0, Arg1)); }
 87     void test_case_4() { int Arg0 = 100000; int Arg1 = 100; int Arg2 = 17442; verify_case(4, Arg2, countSmoothNumbers(Arg0, Arg1)); }
 88 
 89 // END CUT HERE
 90 
 91 };
 92 
 93 // BEGIN CUT HERE
 94 int main()
 95 {
 96 //    freopen( "a.out" , "w" , stdout );    
 97     SmoothNumbers ___test;
 98     ___test.run_test(-1);
 99        return 0;
100 }
101 // END CUT HERE
View Code

 

posted @ 2013-12-30 11:51  Plumrain  阅读(207)  评论(0)  编辑  收藏  举报