README_EN.md

946. Validate Stack Sequences

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Description

Given two sequences pushed and popped with distinct values, return true if and only if this could have been the result of a sequence of push and pop operations on an initially empty stack.

 

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.

 

Note:

<li><code>0 &lt;= pushed.length == popped.length &lt;= 1000</code></li>

<li><code>0 &lt;= pushed[i], popped[i] &lt; 1000</code></li>

<li><code>pushed</code> is a permutation of <code>popped</code>.</li>

<li><code>pushed</code> and <code>popped</code> have distinct values.</li>

Solutions

Python3

Java

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