UVA 12902 Reverse Polish Notation

//跟wyr学的
//其实是贪心
//题解稍后补上

 1 #include<cstdio>

 2 #include<iostream>

 3 #include<cmath>

 4 #include<algorithm>

 5 #include<cstring>

 6 #include<cstdlib>

 7 #include<queue>

 8 #include<vector>

 9 #include<map>

10 #include<stack>

11 #include<string>

12 #define LL long long

13 

14 const int MAXN=0;

15 const int MAXM=0;

16 const int INF=2000000000;

17 

18 using namespace std;

19 

20 int T;

21 char s[100007];

22 

23 int solve(){

24     int len=strlen(s);

25     int MIN=INF;

26     int now=0;

27     int flag=0;

28     for (int i=0;i<len;i++){

29             if (s[i]=='a')

30                 now++;

31             else

32                 now--;

33             if (now==MIN) flag=0;

34             if (now<MIN){

35                     MIN=now;

36                     flag=1;

37             }

38     }

39     if (MIN>=1) return now-1;

40     if (MIN==now) return 1+abs(now);

41     return 1+now-MIN*2-flag;

42 }

43 

44 int main(){

45     scanf("%d",&T);

46     for (int cas=1;cas<=T;cas++){

47             scanf("%s",s);

48             int ans=solve();

49             if (s[0]=='+' && s[1]=='a' && s[2]=='a'){

50                     s[0]='a';

51                     s[1]='a';

52                     s[2]='+';

53                     ans=min(ans,solve()+2);

54             }

55             printf("Case %d: %d\n",cas,ans);

56     }

57     return 0;

58 }

59 /*

60 4

61 a

62 a+a

63 +aa

64 aa++++a

65 */

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