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 */
