946.js

/** ------------------------------------------------------------------------------
 * 
 * 2023-04-13
 * 946. Validate Stack Sequences
 * https://leetcode.com/problems/validate-stack-sequences/description/
 * 
 ------------------------------------------------------------------------------ */
var validateStackSequences = function (pushed, popped) {
  const stack = []
  let i = 0

  for (const num of pushed) {
    stack.push(num)
    while (stack.length > 0 && stack[stack.length - 1] === popped[i]) {
      stack.pop()
      i++
    }
  }
  return stack.length === 0
}

console.log(validateStackSequences([1, 2, 3, 4, 5], [4, 5, 3, 2, 1]))
console.log(validateStackSequences([1, 2, 3, 4, 5], [4, 3, 5, 1, 2]))