力扣1472.設計瀏覽器歷史記錄

• 用雙指針記錄歷史記錄

  • 以及棧頂高度
  • 移動時會直接把之前的記錄消掉

•   class BrowserHistory {int pos=-1;int top=0;string history[5010];public:BrowserHistory(string homepage) {visit(homepage);}void visit(string url) {pos ++;top = pos;history[top] = url;}string back(int steps) {if(steps >pos)steps = pos;pos -= steps;return history[pos];}string forward(int steps) {steps = min(steps,top - pos);pos += steps;return history[pos];}};