Best Time to Buy and Sell Stock with Cooldown LeetCode solution in JavaScript

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/**
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 * @param {number[]} prices
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 * @return {number}
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 */
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var maxProfit = function (prices) {
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  let dp = {};
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  let recursiveProfit = (index, buy) => {
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    if (index >= prices.length) {
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      return 0;
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    }
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    if (dp[index + "_" + buy]) return dp[index + "_" + buy];
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    if (buy) {
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      dp[index + "_" + buy] = Math.max(
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        -prices[index] + recursiveProfit(index + 1, 0),
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        0 + recursiveProfit(index + 1, 1)
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      );
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      return dp[index + "_" + buy];
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    } else {
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      dp[index + "_" + buy] = Math.max(
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        prices[index] + recursiveProfit(index + 2, 1),
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        0 + recursiveProfit(index + 1, 0)
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      );
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      return dp[index + "_" + buy];
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    }
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  };
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  return recursiveProfit(0, 1);
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};