# Validate Stack Sequences

Given two integer arrays `pushed` and `popped` each with distinct values, return `true` if this could have been the result of a sequence of push and pop operations on an initially empty stack, or `false` otherwise.

Example 1:

```Input: pushed = [1,2,3,4,5], popped = [4,5,3,2,1]
Output: true
Explanation: We might do the following sequence:
push(1), push(2), push(3), push(4),
pop() -> 4,
push(5),
pop() -> 5, pop() -> 3, pop() -> 2, pop() -> 1
```

Example 2:

```Input: pushed = [1,2,3,4,5], popped = [4,3,5,1,2]
Output: false
Explanation: 1 cannot be popped before 2.
```

Constraints:

• `1 <= pushed.length <= 1000`
• `0 <= pushed[i] <= 1000`
• All the elements of `pushed` are unique.
• `popped.length == pushed.length`
• `popped` is a permutation of `pushed`.

Solution:

``````class Solution {
public boolean validateStackSequences(int[] pushed, int[] popped) {
int N = pushed.length;
Stack<Integer> stack = new Stack();

int j = 0;
for (int x: pushed) {
stack.push(x);
while (!stack.isEmpty() && j < N && stack.peek() == popped[j]) {
stack.pop();
j++;
}
}

return j == N;
}
}`````` 