模拟 Codeforces Round #297 (Div. 2) A. Vitaliy and Pie

题目传送门

 1 /*
 2     模拟：这就是一道模拟水题，看到标签是贪心，还以为错了呢
 3     题目倒是很长:)
 4 */
 5 #include <cstdio>
 6 #include <algorithm>
 7 #include <iostream>
 8 #include <algorithm>
 9 #include <cstring>
10 using namespace std;
11
12 const int MAXN = 2e5 + 10;
13 const int INF = 0x3f3f3f3f;
14 int cnt[33];
15 char s[MAXN];
16
17 int main(void)        //Codeforces Round #297 (Div. 2) A. Vitaliy and Pie
18 {
19     int n;
20     while (scanf ("%d", &n) == 1)
21     {
22         scanf ("%s", s);    int len = strlen (s);
23         memset (cnt, 0, sizeof (cnt));
24
25         int ans = 0;
26         for (int i=1; i<len; i+=2)
27         {
28             cnt[s[i-1]-‘a‘]++;
29             if (cnt[s[i]-‘A‘])    cnt[s[i]-‘A‘]--;
30             else    ans++;
31         }
32
33         printf ("%d\n", ans);
34     }
35
36     return 0;
37 }
38
39
40 /*
41 3
42 aAbB
43 4
44 aBaCaB
45 5
46 xYyXzZaZ
47 */