CF-div3-635-E - Three Blocks Palindrome| 二分

代码

#include
using namespace std;
typedef long long ll;
const int maxn = 2e5+100;
int a[maxn];
int n;

int main(){
	int t;
	cin>>t;
	while(t--){
		cin>>n;
		vector v[300];
		int ans = 0; 
		for(int i = 1;i<=n;i++) {
			cin>>a[i];
			v[a[i]].push_back(i);
		} 
		for(int i = 1;i<=200;i++){ //枚举a 
			int siz = v[i].size();
			ans = max(ans,siz);
			for(int j = 0;j