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