Submission #5890972

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Source Code Expand

#include <bits/stdc++.h>
#define clr(x) memset(x,0,sizeof x)
#define For(i,a,b) for (int i=(a);i<=(b);i++)
#define Fod(i,b,a) for (int i=(b);i>=(a);i--)
#define fi first
#define se second
#define pb(x) push_back(x)
#define mp(x,y) make_pair(x,y)
#define outval(x) cerr<<#x" = "<<x<<endl
#define outtag(x) cerr<<"---------------"#x"---------------"<<endl
#define outarr(a,L,R) cerr<<#a"["<<L<<".."<<R<<"] = ";\
						For(_x,L,R)cerr<<a[_x]<<" ";cerr<<endl;
using namespace std;
typedef long long LL;
LL read(){
	LL x=0,f=0;
	char ch=getchar();
	while (!isdigit(ch))
		f|=ch=='-',ch=getchar();
	while (isdigit(ch))
		x=(x<<1)+(x<<3)+(ch^48),ch=getchar();
	return f?-x:x;
}
const int N=200005;
int n;
char s[N];
int cnt[N];
int main(){
	cin>>s+1;
	n=strlen(s+1);
	For(i,1,n)
		cnt[s[i]-'a']++;
	LL ans=1;
	For(i,1,n)
		ans+=min(i-1,n-i);
	For(i,1,n-1)
		ans+=min(i,n-i);
	For(i,0,25)
		ans-=(LL)cnt[i]*(cnt[i]-1)/2;
	cout<<ans<<endl;
	return 0;
}

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