1. var maxProfit = function(prices) {
    2.     const n = prices.length;
    3.     const dp = new Array(n).fill(0).map(v => new Array(2).fill(0));
    4.     dp[0][0] = 0, dp[0][1] = -prices[0];
    5.     for (let i = 1; i < n; ++i) {
    6.         dp[i][0] = Math.max(dp[i - 1][0], dp[i - 1][1] + prices[i]);
    7.         dp[i][1] = Math.max(dp[i - 1][1], dp[i - 1][0] - prices[i]);
    8.     }
    9.     return dp[n - 1][0];
    10. };
    1. var maxProfit = function(prices) {
    2.   let dp = [];
    3.   for (let i = -1; i < prices.length; i++) {
    4.     dp[i] = []
    5.     for (let j = 0; j <= 1; j++) {
    6.       dp[i][j] = [];
    7.       dp[i][j][0] = 0;
    8.       dp[i][j][1] = 0;
    9.       if (i === -1) {
    10.         dp[i][j][1] = -Infinity;
    11.       }
    12.       if (j === 0) {
    13.         dp[i][j][1] = -Infinity;
    14.       }
    15.       if (j === -1) {
    16.         dp[i][j][1] = -Infinity;
    17.       }
    18.     }
    19.   }
    20.   for (let i = 0; i < prices.length; i++) {
    21.     for (let j = 1; j <= 1; j++) {
    22.       dp[i][j][0] = Math.max(dp[i - 1][j][0], dp[i - 1][j][1] + prices[i]);
    23.       dp[i][j][1] = Math.max(dp[i - 1][j][1], dp[i - 1][j - 1][0] - prices[i]);
    24.     }
    25.   }
    26.   return dp[prices.length - 1][1][0];
    27. };