字符串处理/贪心 Codeforces Round #307 (Div. 2) B. ZgukistringZ

题目传送门

 /*
     题意：任意排列第一个字符串，使得有最多的不覆盖a/b字符串出现
     字符串处理/贪心：暴力找到最大能不覆盖的a字符串，然后在b字符串中动态得出最优解
     恶心死我了，我最初想输出最多的a，再最多的b，然而并不能保证是最多的:(
 */
 #include <cstdio>
 #include <cstring>
 #include <string>
 #include <iostream>
 #include <algorithm>
 #include <cmath>
 using namespace std;

 const int MAXN = 1e5 + ;
 const int INF = 0x3f3f3f3f;
 char s[MAXN], a[MAXN], b[MAXN];
 int cnt_s[], cnt_a[], cnt_b[];
 int len_s, len_a, len_b;

 int main(void)        //Codeforces Round #307 (Div. 2) B. ZgukistringZ
 {
 //    freopen ("B.in", "r", stdin);

     while (scanf ("%s", s) == )
     {
         scanf ("%s", a);    scanf ("%s", b);
         len_s = strlen (s);    len_a = strlen (a);    len_b = strlen (b);

         memset (cnt_s, , sizeof (cnt_s));
         memset (cnt_a, , sizeof (cnt_a));
         memset (cnt_b, , sizeof (cnt_b));

         for (int i=; i<len_s; ++i)    cnt_s[s[i]-'a']++;
         for (int i=; i<len_a; ++i)    cnt_a[a[i]-'a']++;
         for (int i=; i<len_b; ++i)    cnt_b[b[i]-'a']++;

         int ans_a = , ans_b = ;    int tot = ;
         for (int i=; i<; ++i)    {if (cnt_a[i])    tot = min (tot, cnt_s[i] / cnt_a[i]);}
         for (int i=; i<=tot; ++i)
         {
             int p = ;
             for (int j=; j<; ++j)    {if (cnt_b[j])    p = min (p, (cnt_s[j]  - i * cnt_a[j]) / cnt_b[j]);}
             if (i + p > ans_a + ans_b)    {ans_a = i;    ans_b = p;}
         }

         for (int i=; i<=ans_a; ++i)    printf ("%s", a);
         for (int j=; j<=ans_b; ++j)    printf ("%s", b);
         for (int i=; i<; ++i)
         {
             for (int j=; j<=cnt_s[i]-ans_a*cnt_a[i]-ans_b*cnt_b[i]; ++j)
                 printf ("%c", 'a' + i);
         }
         puts ("");
     }

     return ;
 }