题目简单,关键是灵茶山艾府的代码写起来太优美,不得不记录一下
const int Mod = 1e9+7;
using ll = long long;
ll qmi(ll a,ll b,ll mod){
ll res =1;
while(b){
if(b&1)res = res*a%mod;
a=a*a%mod;
b>>=1;
}
return res;
}
class Solution {
public:
int countAnagrams(string s) {
int cnt[30]{};
int j = 0;
long long ans = 1ll,mul=1ll;
for(int i=0;i<s.size();i++){
if(s[i]==' '){
memset(cnt,0,sizeof cnt);
j = 0;
}else{
mul = mul*++cnt[s[i]-'a']%Mod;
ans = ans*++j%Mod;
}
}
return ans*qmi(mul,Mod-2,Mod)%Mod;
}
};