0946-validate-stack-sequences.java

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

        int i = 0;
        for (int value : pushed) {
            stack.push(value);

            while (i < popped.length && !stack.isEmpty() && stack.peek() == popped[i]) {
                stack.pop();
                i++;
            }
        }

        return stack.isEmpty();
    }
}