Solution.java

class BinaryIndexedTree {
    private int n;
    private int[] c;

    public BinaryIndexedTree(int n) {
        this.n = n;
        this.c = new int[n + 1];
    }

    public void update(int x, int v) {
        while (x <= n) {
            c[x] += v;
            x += x & -x;
        }
    }

    public int query(int x) {
        int s = 0;
        while (x > 0) {
            s += c[x];
            x -= x & -x;
        }
        return s;
    }
}

class Solution {
    public int createSortedArray(int[] instructions) {
        int m = 0;
        for (int x : instructions) {
            m = Math.max(m, x);
        }
        BinaryIndexedTree tree = new BinaryIndexedTree(m);
        int ans = 0;
        final int mod = (int) 1e9 + 7;
        for (int i = 0; i < instructions.length; ++i) {
            int x = instructions[i];
            int cost = Math.min(tree.query(x - 1), i - tree.query(x));
            ans = (ans + cost) % mod;
            tree.update(x, 1);
        }
        return ans;
    }
}