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-8;
const double PI = atan(1.0)*4;
const int maxint = 2139062143;
const int N = 200000;

bool v[1100];

class AvoidingProduct
{
    public:
        vector <int> getTriple(vector <int> a, int n){
            int sz = a.size();
            CLR (v);
            for (int i = 0; i < sz; ++ i) v[a[i]] = 1;
            
            int num = maxint;
            VI cur, tmp;
            for (int i = 1; i <= 1010; ++ i) if (!v[i]){
                if (i*i*i > N) break;
                for (int j = i; j <= 1010; ++ j) if (!v[j]){
                    if (i*j*j > N) break;
                    for (int k = j; k <= 1010; ++ 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 == -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(); if ((Case == -1) || (Case == 5)) 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[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[0]))); int Arg1 = 1000; int Arr2[] = {51, 51, 51 }; vector <int> Arg2(Arr2, Arr2 + (sizeof(Arr2) / sizeof(Arr2[0]))); verify_case(0, Arg2, getTriple(Arg0, Arg1)); }
    void test_case_1() { int Arr0[] = {1}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[0]))); int Arg1 = 10; int Arr2[] = {2, 2, 2 }; vector <int> Arg2(Arr2, Arr2 + (sizeof(Arr2) / sizeof(Arr2[0]))); verify_case(1, Arg2, getTriple(Arg0, Arg1)); }
    void test_case_2() { int Arr0[] = {1,2}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[0]))); int Arg1 = 10; int Arr2[] = {3, 3, 3 }; vector <int> Arg2(Arr2, Arr2 + (sizeof(Arr2) / sizeof(Arr2[0]))); verify_case(2, Arg2, getTriple(Arg0, Arg1)); }
    void test_case_3() { int Arr0[] = {1,3}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[0]))); int Arg1 = 12; int Arr2[] = {2, 2, 2 }; vector <int> Arg2(Arr2, Arr2 + (sizeof(Arr2) / sizeof(Arr2[0]))); verify_case(3, Arg2, getTriple(Arg0, Arg1)); }
    void test_case_4() { int Arr0[] = {1,3}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[0]))); int Arg1 = 13; int Arr2[] = {2, 2, 4 }; vector <int> Arg2(Arr2, Arr2 + (sizeof(Arr2) / sizeof(Arr2[0]))); verify_case(4, Arg2, getTriple(Arg0, Arg1)); }
    void test_case_5() { int Arr0[] = {1,15}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[0]))); int Arg1 = 90; int Arr2[] = {2, 5, 9 }; vector <int> Arg2(Arr2, Arr2 + (sizeof(Arr2) / sizeof(Arr2[0]))); verify_case(5, Arg2, getTriple(Arg0, Arg1)); }

// END CUT HERE

};

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