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class Solution {
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 public:
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  bool validateStackSequences(vector<int> &pushed, vector<int> &popped) {
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    stack<int> st; // Create a stack
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    int j = 0; // Intialise one pointer pointing on popped array
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    for (auto val : pushed) {
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      st.push(val);                                    // insert the values in stack
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      while (st.size() > 0 && st.top() == popped[j]) { // if st.peek() values equal to popped[j];
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        st.pop();                                      // then pop out
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        j++;                                           // increment j
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      }
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    }
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    return st.size() == 0; // check if stack is empty return true else false
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  }
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};