剑指Offer、栈的压入、弹出序列

Problem: 946. 验证栈序列

入栈数组入栈，遇到弹出栈相同元素时弹出，最后判断栈是否为空。特判条件记得特判

Code

class Solution {
    public boolean validateStackSequences(int[] pushed, int[] popped) {
        if(pushed.length==0&&pushed.length==popped.length)return true;
        if(pushed.length!=popped.length)return false;
        Stack<Integer>stack=new Stack<>();
        for(int i=0,j=0;i<popped.length;i++)
        {
            while((stack.isEmpty()||popped[i]!=stack.peek())&&j<popped.length)
            {
                stack.push(pushed[j]);
                j++;
            }
            if(stack.peek()==popped[i])stack.pop();

        }
        if(!stack.isEmpty())return false;
        else return true;
    }
}