’‘’#include[HTML_REMOVED]
using namespace std;
int a[100001]; bool b[100001];
int main() {
std::ios::sync_with_stdio(false);
std::cin.tie(0);
int n,i,j,kk;
cin >> n;
for (i = 0; i < n; i)cin >> a[i];
for (i = 0; i < 100001; i)b[i] = 0;
j = 0;
b[a[0]] = 1;
kk = 1;
for (i = 1; i < n; i)
{
while(b[a[i]]==1)b[a[j]] = 0;
//从上次找到的合理串前进一位以后最多一次重复;如果[j,i]有重复则[j,i+k]均有重复,可直接忽略
if (i - j + 1 > kk)kk = i - j + 1;
b[a[i]] = 1;
}
cout << kk;
}’‘’