SRM 399(1-250pt)

DIV1 250pt

题意：给出一个size不超过50的数组a和整数n，求x,y,z使得|n - x*y*z|最小，且x,y,z均不再数组a中。若有多组xyz使得|n-x*y*z|最小，输出字典序最小的。a中的元素和n <= 1000。

解法：我直接写了一个暴力扫的方法，x*y*z上限设成了10000....发现如果a中含有1,2,3....50，就会WA，因为这样的话x*y*z的需要达到51*51*51。后来又写了一个方法也错了.....没做出来看了题解，发现它是div2的1000突然就感觉到安慰了.......

　　　要观察到一个东西，就是x,y,z都不可能超过n + 51。然后暴力就可以了，加一个break语句，当x*y*z > 200000时。

　　　想了一下，也就是说，其实可以不用观察到那个结论，只需要对xyz写3个for语句从1到1010，然后在x*y*z > 200000时break，这道题就能过了....

tag:think

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

  */
 // END CUT HERE
 #line 11 "AvoidingProduct.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 CLR(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<<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-;
 const double PI = atan(1.0)*;
 const int maxint = ;
 const int N = ;

 bool v[];

 class AvoidingProduct
 {
     public:
         vector <int> getTriple(vector <int> a, int n){
             int sz = a.size();
             CLR (v);
             for (int i = ; i < sz; ++ i) v[a[i]] = ;

             int num = maxint;
             VI cur, tmp;
             for (int i = ; i <= ; ++ i) if (!v[i]){
                 if (i*i*i > N) break;
                 for (int j = i; j <= ; ++ j) if (!v[j]){
                     if (i*j*j > N) break;
                     for (int k = j; k <= ; ++ k) if (!v[k]){
                         int mul = i * j * k;
                         int t_num = abs(n - mul);
                         if (num == t_num){
                             tmp.clear();
                             tmp.PB (i); tmp.PB (j); tmp.PB (k);
                         }
                         if (t_num < num || (t_num == num && tmp < cur)){
                             num = t_num;
                             cur.clear();
                             cur.PB (i); cur.PB (j); cur.PB (k);
                         }
                         if (mul > N) break;
                     }
                 }
             }
             return cur;
         }

 // BEGIN CUT HERE
     public:
     void run_test(int Case) { if ((Case == -) || (Case == )) test_case_0(); if ((Case == -) || (Case == )) test_case_1(); if ((Case == -) || (Case == )) test_case_2(); if ((Case == -) || (Case == )) test_case_3(); if ((Case == -) || (Case == )) test_case_4(); if ((Case == -) || (Case == )) test_case_5(); }
     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 vector <int> &Expected, const vector <int> &Received) { cerr << "Test Case #" << Case << "..."; if (Expected == Received) cerr << "PASSED" << endl; else { cerr << "FAILED" << endl; cerr << "\tExpected: " << print_array(Expected) << endl; cerr << "\tReceived: " << print_array(Received) << endl; } }
     void test_case_0() { int Arr0[] = {, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , }; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; int Arr2[] = {, ,  }; vector <int> Arg2(Arr2, Arr2 + (sizeof(Arr2) / sizeof(Arr2[]))); verify_case(, Arg2, getTriple(Arg0, Arg1)); }
     void test_case_1() { int Arr0[] = {}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; int Arr2[] = {, ,  }; vector <int> Arg2(Arr2, Arr2 + (sizeof(Arr2) / sizeof(Arr2[]))); verify_case(, Arg2, getTriple(Arg0, Arg1)); }
     void test_case_2() { int Arr0[] = {,}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; int Arr2[] = {, ,  }; vector <int> Arg2(Arr2, Arr2 + (sizeof(Arr2) / sizeof(Arr2[]))); verify_case(, Arg2, getTriple(Arg0, Arg1)); }
     void test_case_3() { int Arr0[] = {,}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; int Arr2[] = {, ,  }; vector <int> Arg2(Arr2, Arr2 + (sizeof(Arr2) / sizeof(Arr2[]))); verify_case(, Arg2, getTriple(Arg0, Arg1)); }
     void test_case_4() { int Arr0[] = {,}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; int Arr2[] = {, ,  }; vector <int> Arg2(Arr2, Arr2 + (sizeof(Arr2) / sizeof(Arr2[]))); verify_case(, Arg2, getTriple(Arg0, Arg1)); }
     void test_case_5() { int Arr0[] = {,}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; int Arr2[] = {, ,  }; vector <int> Arg2(Arr2, Arr2 + (sizeof(Arr2) / sizeof(Arr2[]))); verify_case(, Arg2, getTriple(Arg0, Arg1)); }

 // END CUT HERE

 };

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