SRM 406(1-250pt, 1-500pt)

DIV1 250pt

题意：有几家宠物店，vecort<int>A表示每家宠物店含有小狗占小狗总数的百分比。现在要做扇形统计图统计每家店的小狗百分比，如下图，问作出来的扇形统计图中最多含有多少对半径夹角为180度。(左图两对，右图一对) (A.size() <= 8)

解法：因为A.size() <= 8，所以直接暴力枚举A中元素的全排列就好了。我的代码又写复杂了。。。一是枚举全排列可以用next_permutation()函数，另一个是对每个排列统计数量的时候写复杂了，不需要算j < i的情况，只要不除以2就行了。

tag:brute-force

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

  */
 // END CUT HERE
 #line 11 "SymmetricPie.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-;
 const double PI = atan(1.0)*;
 const int inf =  / ;

 int n, ans;
 VI an, dn;
 bool mp[];
 int sum[];

 void dfs(int x)
 {
     if (x == n){
         clr0 (sum); sum[] = dn[an[]];
         for (int i = ; i < n; ++ i)
             sum[i] = sum[i-] + dn[an[i]];

         int cnt = ;
         for (int i = ; i < n; ++ i)
             for (int j = ; j < n; ++ j){
                 int tmp = j > i ? sum[j] - sum[i] : sum[n-] - sum[i] + sum[j];
                 if (tmp == ) ++ cnt;
             }
         ans = max(ans, cnt/);
         return ;
     }

     for (int i = ; i < n; ++ i) if (!mp[i]){
         an.pb (i); mp[i] = ;
         dfs (x + );
         an.pop_back(); mp[i] = ;
     }
 }

 class SymmetricPie
 {
     public:
         int getLines(vector <int> D){
             dn = D;
             ans = ; n = sz(dn);
             clr0 (mp); an.clear();
             dfs ();
             return ans;
         }

 // 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(); }
     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 << "\tExpected: \"" << Expected << '\"' << endl; cerr << "\tReceived: \"" << Received << '\"' << endl; } }
     void test_case_0() { int Arr0[] = {,,,}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; verify_case(, Arg1, getLines(Arg0)); }
     void test_case_1() { int Arr0[] = {,,}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; verify_case(, Arg1, getLines(Arg0)); }
     void test_case_2() { int Arr0[] = {,}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; verify_case(, Arg1, getLines(Arg0)); }
     void test_case_3() { int Arr0[] = {,,,,,}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; verify_case(, Arg1, getLines(Arg0)); }
     void test_case_4() { int Arr0[] = {,,}; vector <int> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; verify_case(, Arg1, getLines(Arg0)); }

 // END CUT HERE

 };

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

DIV1 500pt

题意：有一张纸，纸上有n * m格，每个格子上有一个数字。若将纸折叠(可以不对折，但是折痕只能在格与格之间，不能穿过格子。)，折叠后重合的两个格子原先的值之和即为现在的值，比如1*2的纸含有两个数字1,2，折叠后含有一个数字3。折叠完成后，最终纸上所有数字中最大的为max。问随意折叠多少次，求max最大为多少。n <= 12，m <= 12，-100 <= A[i][j] <= 100

解法：也是暴力，只不过要预处理+暴力。只是开始我想到暴力的时候觉得这样不好写，而且感觉好慢可能不行，就没有细想了。。。所以也没有做出来。暴力的方法是，先预处理哪些列最终可能折叠在一起，再预处理哪些行最终可能会折叠在一起，然后对于处理出来的东西枚举就好了。我看了官方题解也没想好怎么写，然后又看了它推荐的代码才弄懂。

tag:brute-force

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

  */
 // END CUT HERE
 #line 11 "FoldThePaper.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-;
 const double PI = atan(1.0)*;
 const int inf =  / ;

 int n, m;
 int an[][];
 bool can[<<];
 vector<vi> row, col;

 vi getvec(int x, int f)
 {
     vi v;
     for (int i = ; i < (f ? m : n); ++ i)
         if (x & (<<i)) v.pb (i);
     return v;
 }

 void rec(vi v){
     //for (int i = 0; i < sz(v); ++ i)
         //tst (v[i]);
     //cout << endl;
     int n = sz(v);
     for (int i = ; i < n; ++ i)
         can[v[i]] = ;
     for (int i = ; i < n; ++ i){
         vi nv(max(i, n-i));
         if (i <= n/){
             for (int j = i; j < n; ++ j)
                 nv[j-i] = v[j];
             for (int j = , k = i-; j < i; ++ j, -- k)
                 nv[j] |= v[k];
         }
         else{
             for (int j = ; j < i; ++ j)
                 nv[j] = v[j];
             for (int j = i, k = i-; j < n; ++ j, -- k)
                 nv[k] |= v[j];
         }
         rec(nv);
     }
 }

 class FoldThePaper
 {
     public:
         int getValue(vector <string> pap){
             n = sz(pap);
             stringstream stm;
             for (int i = ; i < n; ++ i){
                 stm << pap[i]; m = ;
                 while (stm >> an[i][m]) ++ m;
                 stm.clear();
             }
             clr0 (can);
             vi v;
             for (int i = ; i < n; ++ i) v.pb (<<i);
             rec(v);
             row.clear();
             for (int i = ; i < (<<n); ++ i) if (can[i])
                 row.pb (getvec(i, ));

             v.clear(); clr0 (can);
             for (int i = ; i < m; ++ i) v.pb (<<i);
             rec(v);
             col.clear();
             for (int i = ; i < (<<m); ++ i) if (can[i])
                 col.pb (getvec(i, ));

             int ans = -inf;
             for (int i = ; i < sz(row); ++ i)
                 for (int j = ; j < sz(col); ++ j){
                     int tmp = -inf;
                     for (int t = ; t < sz(row[i]); ++ t)
                         for (int k = ; k < sz(col[j]); ++ k){
                             if (tmp == -inf) tmp = an[row[i][t]][col[j][k]];
                             else tmp += an[row[i][t]][col[j][k]];
                         }
                     ans = max(tmp, ans);
                 }
             return ans;
         }

 // 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(); }
     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 << "\tExpected: \"" << Expected << '\"' << endl; cerr << "\tReceived: \"" << Received << '\"' << endl; } }
     void test_case_0() { string Arr0[] = {
 "1 1 1",
 "1 1 1"
 }; vector <string> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; verify_case(, Arg1, getValue(Arg0)); }
     void test_case_1() { string Arr0[] = {
 "1 -1",
 "1 -1"
 }; vector <string> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; verify_case(, Arg1, getValue(Arg0)); }
     void test_case_2() { string Arr0[] = {
 "1 -1 -1 1",
 "-1 -1 -1 -1",
 "-1 -1 -1 -1",
 "1 -1 -1 1"
 }; vector <string> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; verify_case(, Arg1, getValue(Arg0)); }
     void test_case_3() { string Arr0[] = {
 "20 13 -2 100",
 "-12 0 4 -3",
 "4 1 -36 21"
 }; vector <string> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; verify_case(, Arg1, getValue(Arg0)); }
     void test_case_4() { string Arr0[] = {
 ""
 }; vector <string> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[]))); int Arg1 = ; verify_case(, Arg1, getValue(Arg0)); }

 // END CUT HERE

 };

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