SRM 394(1-250pt)

DIV1 250pt

题意：给定一个字符串s('a'-'z')，计其中出现次数最多和最少的字母分别出现c1次和c2次，若在s中去掉最多k个字母，求去掉以后c1 - c2的最小值。

解法：做题的时候，想到了用dfs暴力枚举，然后TLE了。然后想到了枚举c2，求c1的最小值，最后写了比较麻烦的代码，过了。然后看了题解才发现，枚举c1和c2。。。。。

　　　真的是看到'a' - 'z'就应该想到这种方法。。。。

tag:think, brute-force

  1 // BEGIN CUT HERE
  2 /*
  3  * Author:  plum rain
  4  * score :
  5  */
  6 /*
  7 
  8  */
  9 // END CUT HERE
 10 #line 11 "RoughStrings.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 mp make_pair
 41 #define sz(v) ((int)(v).size())
 42 #define all(t) t.begin(),t.end()
 43 #define zero(x) (((x)>0?(x):-(x))<eps)
 44 #define out(x) cout<<#x<<":"<<(x)<<endl
 45 #define tst(a) cout<<a<<" "
 46 #define tst1(a) cout<<#a<<endl
 47 #define CINBEQUICKER std::ios::sync_with_stdio(false)
 48 
 49 typedef vector<int> VI;
 50 typedef vector<string> VS;
 51 typedef vector<double> VD;
 52 typedef pair<int, int> pii;
 53 typedef long long int64;
 54 
 55 const double eps = 1e-8;
 56 const double PI = atan(1.0)*4;
 57 const int inf = 2139062143 / 2;
 58 
 59 int num[500], n2[500], n1[500];
 60 int idx[500], all;
 61 pii an[100];
 62 
 63 int gao(int k)
 64 {
 65     clr0 (n2);
 66     for (int i = 0; i < 26; ++ i)
 67         ++ n2[num[i]];
 68     int pos = 50;
 69     while (!n2[pos]) -- pos;
 70     while (k > 0){
 71         if (pos < 0) return 0;
 72         k -= n2[pos];
 73         n2[pos-1] += n2[pos];
 74         n2[pos--] = 0;
 75     }
 76     if (!k) return pos;
 77     return pos + 1;
 78 }
 79 
 80 class RoughStrings
 81 {
 82     public:
 83         int minRoughness(string s, int k){
 84             clr0 (num);
 85             for (int i = 0; i < sz(s); ++ i)
 86                 ++ num[s[i] - 'a'];
 87             all = 0;
 88             for (int i = 0; i < 26; ++ i)
 89                 if (num[i]) n1[all++] = num[i];
 90             if (all == 1) return 0;
 91             sort(n1, n1+all);
 92             int ans = max(gao(k) - n1[0], 0), use = 0;
 93             for (int i = 0; i < all; ++ i){
 94                 use += n1[i];
 95                 if (k < use) break;
 96                 if (i == all-1) ans = 0;
 97                 else ans = min(ans, max(gao(k-use) - n1[i+1], 0));
 98             }
 99             return ans;
100         }
101         
102 // BEGIN CUT HERE
103     public:
104     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(); }
105     private:
106     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(); }
107     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; } }
108     void test_case_0() { string Arg0 = "aaaaabbc"; int Arg1 = 1; int Arg2 = 3; verify_case(0, Arg2, minRoughness(Arg0, Arg1)); }
109     void test_case_1() { string Arg0 = "aaaabbbbc"; int Arg1 = 5; int Arg2 = 0; verify_case(1, Arg2, minRoughness(Arg0, Arg1)); }
110     void test_case_2() { string Arg0 = "veryeviltestcase"; int Arg1 = 1; int Arg2 = 2; verify_case(2, Arg2, minRoughness(Arg0, Arg1)); }
111     void test_case_3() { string Arg0 = "gggggggooooooodddddddllllllluuuuuuuccckkk"; int Arg1 = 5; int Arg2 = 3; verify_case(3, Arg2, minRoughness(Arg0, Arg1)); }
112     void test_case_4() { string Arg0 = "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz"; int Arg1 = 17; int Arg2 = 0; verify_case(4, Arg2, minRoughness(Arg0, Arg1)); }
113     void test_case_5() { string Arg0 = "bbbccca"; int Arg1 = 2; int Arg2 = 0; verify_case(5, Arg2, minRoughness(Arg0, Arg1)); }
114 
115 // END CUT HERE
116 
117 };
118 
119 // BEGIN CUT HERE
120 int main()
121 {
122 //    freopen( "a.out" , "w" , stdout );    
123     RoughStrings ___test;
124     ___test.run_test(-1);
125        return 0;
126 }
127 // END CUT HERE

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