用快排思路解决逆序对问题

#include
#include
#define rep(i, n) for(i=0;i> k;
	rep(i, k) cin >> a[i];
	quicksort(0, k - 1);
	rep(i, k) cout << a[i];
	cout << hit << endl;
	getchar(); getchar(); //crash
}


void quicksort(int l, int r){
	if (l < r){
		int round = l + rand() % (r - l + 1);
		int set = a[round];
		int i, al = 0, br = 0, il = l, ir, count = 0;
		repi(i, l, r){
			if (a[i] set)
			{
				b[ir++] = a[i];
				al++;
				if (i < round)
					hit++;
			}
			else if (a[i] < set)
			{
				b[il++] = a[i];
				br++;
				if (i>round)
					hit++;
				hit += al;
			}
		}

		repi(i, l, r){
			a[i] = b[i];
		}
	quicksort(l, count);
	quicksort(count + 1, r);
	}
}