DIV1 250pt
题意：给定整数n和k，问最少需要多少个n连接在一起形成的新整数t，使得t是k的倍数。如果不能形成倍数，输出-1。k <= 10^5，n <= 10^9。
解法：不断增加连接的n的数量，如果新形成的数除以k的余数已经出现过，说明出现循环，说明该输出-1。否则，最多执行k次就能得到答案。所以，总的来说最多执行k次，可以直接暴力。
tag:brute-force
1 // BEGIN CUT HERE 2 /* 3 * Author: plum rain 4 * score : 5 */ 6 /* 7 8 */ 9 // END CUT HERE 10 #line 11 "ConcatenateNumber.cpp" 11 #include <sstream> 12 #include <stdexcept> 13 #include <functional> 14 #include <iomanip> 15 #include <numeric> 16 #include <fstream> 17 #include <cctype> 18 #include <iostream> 19 #include <cstdio> 20 #include <vector> 21 #include <cstring> 22 #include <cmath> 23 #include <algorithm> 24 #include <cstdlib> 25 #include <set> 26 #include <queue> 27 #include <bitset> 28 #include <list> 29 #include <string> 30 #include <utility> 31 #include <map> 32 #include <ctime> 33 #include <stack> 34 35 using namespace std; 36 37 #define clr0(x) memset(x, 0, sizeof(x)) 38 #define clr1(x) memset(x, -1, sizeof(x)) 39 #define pb push_back 40 #define sz(v) ((int)(v).size()) 41 #define all(t) t.begin(),t.end() 42 #define zero(x) (((x)>0?(x):-(x))<eps) 43 #define out(x) cout<<#x<<":"<<(x)<<endl 44 #define tst(a) cout<<a<<" " 45 #define tst1(a) cout<<#a<<endl 46 #define CINBEQUICKER std::ios::sync_with_stdio(false) 47 48 typedef vector<int> vi; 49 typedef vector<string> vs; 50 typedef vector<double> vd; 51 typedef pair<int, int> pii; 52 typedef long long int64; 53 54 const double eps = 1e-8; 55 const double PI = atan(1.0)*4; 56 const int inf = 2139062143 / 2; 57 58 class ConcatenateNumber 59 { 60 public: 61 bool an[100005]; 62 int getSmallest(int n, int k){ 63 clr0 (an); 64 int64 nn = n, tmp = n % k, ten = 1; 65 while (n) 66 ten *= 10, n /= 10; 67 int cnt = 1; 68 while (1){ 69 if (tmp == 0) return cnt; 70 if (an[tmp]) return -1; 71 else an[tmp] = 1; 72 73 tmp = (tmp * ten + nn)% k; 74 ++ cnt; 75 } 76 } 77 78 // BEGIN CUT HERE 79 public: 80 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(); } 81 private: 82 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(); } 83 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 << " Expected: "" << Expected << '"' << endl; cerr << " Received: "" << Received << '"' << endl; } } 84 void test_case_0() { int Arg0 = 2; int Arg1 = 9; int Arg2 = 9; verify_case(0, Arg2, getSmallest(Arg0, Arg1)); } 85 void test_case_1() { int Arg0 = 121; int Arg1 = 11; int Arg2 = 1; verify_case(1, Arg2, getSmallest(Arg0, Arg1)); } 86 void test_case_2() { int Arg0 = 1; int Arg1 = 2; int Arg2 = -1; verify_case(2, Arg2, getSmallest(Arg0, Arg1)); } 87 void test_case_3() { int Arg0 = 35; int Arg1 = 98765; int Arg2 = 9876; verify_case(3, Arg2, getSmallest(Arg0, Arg1)); } 88 void test_case_4() { int Arg0 = 1000000000; int Arg1 = 3; int Arg2 = 3; verify_case(4, Arg2, getSmallest(Arg0, Arg1)); } 89 90 // END CUT HERE 91 92 }; 93 94 // BEGIN CUT HERE 95 int main() 96 { 97 // freopen( "a.out" , "w" , stdout ); 98 ConcatenateNumber ___test; 99 ___test.run_test(-1); 100 return 0; 101 } 102 // END CUT HERE