K Inverse Pairs Array LeetCode solution in JavaScript

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var kInversePairs = function (n, k) {
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  const dp = new Array(n + 1).fill(0).map((el) => new Array(k + 1).fill(0));
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  const MOD = Math.pow(10, 9) + 7;
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  for (let i = 0; i < n + 1; i++) {
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    dp[i][0] = 1;
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  }
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  for (let i = 1; i <= n; i++) {
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    for (let j = 1; j <= k; j++) {
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      dp[i][j] =
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        dp[i][j - 1] +
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        (dp[i - 1][j] % MOD) -
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        ((j >= i ? dp[i - 1][j - i] : 0) % MOD);
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    }
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  }
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  return dp[n][k] % MOD;
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};