946

class Solution {
public:
    bool validateStackSequences(vector<int>& pushed, vector<int>& popped) {
        int i, j;
        i=j=0;
        for(int x: pushed){
            pushed[i++] = x;
            while(i>0 && pushed[i-1] == popped[j])
                i--, j++;
        }
        return i == 0;
    }
};