1475.js

/** ------------------------------------------------------------------------------
 * 
 * 1475. Final Prices With a Special Discount in a Shop
 * Topics: Array, Monotonic Stack
 * https://leetcode.com/problems/final-prices-with-a-special-discount-in-a-shop/?envType=daily-question&envId=2024-12-18
 * 
 ------------------------------------------------------------------------------ */
/**
 * @param {number[]} prices
 * @return {number[]}
 */
var finalPrices = function (prices) {
  let answer = []

  for (let i = 0; i < prices.length; i++) {
    const price = prices[i]
    const salesIndex = prices.findIndex((v, index) => v <= price && index > i)

    if (salesIndex === -1) {
      answer.push(price)
    } else {
      answer.push(price - prices[salesIndex])
    }
  }

  return answer
}

/**
 * monotonic stack
 */
var finalPrices = function (prices) {
  let stack = []
  let answer = []

  for (let i = 0; i < prices.length; i++) {
    const price = prices[i]

    while (stack.length > 0 && prices[stack[stack.length - 1]] >= price) {
      console.log("while start")
      console.log(stack)
      const index = stack.pop()
      answer[index] = prices[index] - price
      console.log("while end: ", stack)
    }

    stack.push(i)
  }

  return answer
}

console.log(finalPrices([8, 4, 6, 2, 3]))