div1 250pt:
题意：用RGB三种颜色的球摆N层的三角形，要求相邻的不同色，给出RGB的数量，问最多能摆几个
解法：三种颜色的数量要么是全一样，要么是两个一样，另外一个比他们多一个，于是可以分类讨论：对于数量全一样的，直接算;对于另外的，我们可以先不考虑多出来的那一个，也是正常放，然后看最后剩下的位置能不能放完所有多出来的那一个，这个可以二分。
1 // BEGIN CUT HERE 2 3 // END CUT HERE 4 #line 5 "FoxPaintingBalls.cpp" 5 #include<cstdio> 6 #include<cstring> 7 #include<cstdlib> 8 #include<ctime> 9 #include<cmath> 10 #include<cassert> 11 #include<iostream> 12 #include<string> 13 #include<sstream> 14 #include<vector> 15 #include<map> 16 #include<set> 17 #include<queue> 18 #include<stack> 19 #include<algorithm> 20 using namespace std; 21 typedef long long ll; 22 typedef pair<int,int> pii; 23 class FoxPaintingBalls 24 { 25 public: 26 long long theMax(long long R, long long G, long long B, int N){ 27 //$CARETPOSITION$ 28 if(N == 1)return R+G+B; 29 ll total = 1LL*N*(N + 1) / 2; 30 ll least = total / 3; 31 ll maxn = min(min(R,G),B) / least; 32 if(total % 3 == 0)return maxn; 33 ll answer = 0,left = 0,right = maxn; 34 while(left <= right){ 35 // cout << "L: "<<l<<" R: "<<r<<endl; 36 ll mid = (left + right) >> 1; 37 ll r = R - mid * least,g = G - mid * least,b = B - mid * least; 38 if((r + g + b) >= mid){ 39 answer = mid; 40 left = mid + 1; 41 }else{ 42 right = mid - 1; 43 } 44 } 45 return answer; 46 47 48 49 50 } 51 52 // BEGIN CUT HERE 53 public: 54 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(); if ((Case == -1) || (Case == 6)) test_case_6(); } 55 private: 56 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(); } 57 void verify_case(int Case, const long long &Expected, const long long &Received) { cerr << "Test Case #" << Case << "..."; if (Expected == Received) cerr << "PASSED" << endl; else { cerr << "FAILED" << endl; cerr << "\tExpected: \"" << Expected << '\"' << endl; cerr << "\tReceived: \"" << Received << '\"' << endl; } } 58 void test_case_0() { long long Arg0 = 2LL; long long Arg1 = 2LL; long long Arg2 = 2LL; int Arg3 = 3; long long Arg4 = 1LL; verify_case(0, Arg4, theMax(Arg0, Arg1, Arg2, Arg3)); } 59 void test_case_1() { long long Arg0 = 1LL; long long Arg1 = 2LL; long long Arg2 = 3LL; int Arg3 = 3; long long Arg4 = 0LL; verify_case(1, Arg4, theMax(Arg0, Arg1, Arg2, Arg3)); } 60 void test_case_2() { long long Arg0 = 8LL; long long Arg1 = 6LL; long long Arg2 = 6LL; int Arg3 = 4; long long Arg4 = 2LL; verify_case(2, Arg4, theMax(Arg0, Arg1, Arg2, Arg3)); } 61 void test_case_3() { long long Arg0 = 7LL; long long Arg1 = 6LL; long long Arg2 = 7LL; int Arg3 = 4; long long Arg4 = 2LL; verify_case(3, Arg4, theMax(Arg0, Arg1, Arg2, Arg3)); } 62 void test_case_4() { long long Arg0 = 100LL; long long Arg1 = 100LL; long long Arg2 = 100LL; int Arg3 = 4; long long Arg4 = 30LL; verify_case(4, Arg4, theMax(Arg0, Arg1, Arg2, Arg3)); } 63 void test_case_5() { long long Arg0 = 19330428391852493LL; long long Arg1 = 48815737582834113LL; long long Arg2 = 11451481019198930LL; int Arg3 = 3456; long long Arg4 = 5750952686LL; verify_case(5, Arg4, theMax(Arg0, Arg1, Arg2, Arg3)); } 64 void test_case_6() { long long Arg0 = 1LL; long long Arg1 = 1LL; long long Arg2 = 1LL; int Arg3 = 1; long long Arg4 = 3LL; verify_case(6, Arg4, theMax(Arg0, Arg1, Arg2, Arg3)); } 65 66 // END CUT HERE 67 68 }; 69 // BEGIN CUT HERE 70 int main(){ 71 FoxPaintingBalls ___test; 72 ___test.run_test(-1); 73 return 0; 74 } 75 // END CUT HERE