class Solution { public: int maxLength(vector<int>& arr) { int v[100010] = { 0 }; int n = arr.size(); int start = 0; int ret = 0; for(int i=0;i<n;i++) { v[arr[i]]++; while(v[arr[i]]>1) { v[arr[start]]--; start++; } ret = max(ret,i-start+1); } return ret; } };