求问复杂度

#include<bits/stdc++.h>
using namespace std;
int t,m,n,cnt,a[200005];long long ans;
string s;char lst;
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);cout.tie(0);
	cin>>t;
	while(t--){
		cin>>n>>s;ans=m=0;cnt=1;
		for(int i=0;i<=n;i++) a[i]=0;
		if(s[0]=='=') cnt=2;
		else a[1]=1;lst=s[0];
		for(int i=1;i<n-1;i++){
			if(s[i]=='=') a[i+1]=a[i],cnt++;
			else if(s[i]==s[i-1]) a[i+1]=a[i]+1,cnt=1;
			else if(s[i]!=lst) a[i+1]=cnt,cnt=1,lst=s[i];
			else if(s[i]==lst) a[i+1]=a[i]+cnt,cnt=1;
		}
		for(int i=0;i<=n;i++) ans+=a[i];
		cout<<ans<<"\n";
	}
	return 0;
}