题解 | #栈的压入、弹出序列#

import java.util.ArrayList;
import java.util.Stack;


public class Solution {
    public boolean IsPopOrder(int [] pushA,int [] popA) {
        Stack<Integer>st = new Stack<Integer>();
        int i=0,j=0;
        while(j<popA.length && i<pushA.length){
            while(j<popA.length && i<pushA.length && popA[j]!=pushA[i]){
                st.add(pushA[i]);
                i++;
            }
            if(i<pushA.length) st.add(pushA[i++]);
            while(st.size()>0 && popA[j]==st.peek()){
                st.pop();
                j++;
            }
        }
        if(st.size()==0) return true;
        return false;
    }
}