剑指 Offer 31. 栈的压入、弹出序列(C++实现)

剑指 Offer 31. 栈的压入、弹出序列

剑指 Offer 31. 栈的压入、弹出序列

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思路

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class Solution {
    //思路是：遍历入栈数组pushed，和弹栈数组popped，用一个新的栈pushSt来做中间层，用来模拟出栈和入栈是否匹配成功；就是pushed数组入栈pushSt，而popped数组向前走遍历就类似出栈pushSt
    //只要是满足，遍历完弹栈数组poped，那么就表示模拟成功，该序列弹栈poped数组是合法的
public:
    bool validateStackSequences(vector<int>& pushed, vector<int>& popped) {
        stack<int> pushSt;
        int pushi = 0;
        int popi = 0;
        //只要发现pushed[pushi]的值和popped[popi]的值不相等，那么我们就入栈pushed[pushi]
        while(pushi <pushed.size()){
            pushSt.push(pushed[pushi]);
            pushi++;

            while(!pushSt.empty() && pushSt.top() == popped[popi]){
                pushSt.pop();
                popi++;
            }
        }
        return popi == popped.size();
    }
};