所有不同的字母都作为一次贡献是最大的。
#pragma comment(linker, "/STACK:1024000000,1024000000") #include<cstdio> #include<cstring> #include<cmath> #include<algorithm> #include<vector> #include<map> #include<set> #include<queue> #include<stack> #include<iostream> using namespace std; typedef long long LL; const double pi=acos(-1.0),eps=1e-8; void File() { freopen("D:\in.txt","r",stdin); freopen("D:\out.txt","w",stdout); } template <class T> inline void read(T &x) { char c = getchar(); x = 0;while(!isdigit(c)) c = getchar(); while(isdigit(c)) { x = x * 10 + c - '0'; c = getchar(); } } const int maxn=100010; char s[maxn]; int T,ans,f[maxn]; int main() { int cas=1; scanf("%d",&T); while(T--) { memset(f,0,sizeof f); ans=0; scanf("%s",s); for(int i=0;s[i];i++) if(f[s[i]]==0) ans++,f[s[i]]=1; printf("Case #%d: %d ",cas++,ans); } return 0; }