水果成篮
class Solution { public: int totalFruit(vector<int>& a) { int ans = 1 , n = a.size(); int l=0,r = l+1,lr =l; while(l<n) { int x1 = a[l],x2 = -1; while(r<n && (x2==-1 || a[r]==x1 || a[r]==x2) ){ if(a[r]!=x1 && x2==-1){ x2 = a[r]; } if(a[r] != a[lr]){ lr = r; } r++; } ans = max(ans,r-l); if(r==n){ break; } l = lr; } return ans; } };