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public static int two SumReallyFastUnique (int[] a) { Arrays. sort (a); int lo = 0; int hi = a.length-1; int count = 0; while (lo <hi) { int sum = a[10] + a[hi]; if (sum < 0) lo++; else if (sum > 0) --hi; else { count++; lo++; --hi; } } return count; } 1 o lg N N O N lg N O N2 O N2 lg N

public static double accumulateSorted (double[] a) { Arrays. sort (a); double sum = 0.0; for (int i = a.length-1; i >= 0; i--) += a; return sum; } sum 1 lg N O N () N lg N () N2 N2 lg N

public static int multiply (int a, int b) { int result = 0; while (b != 0) { if (b% 2 != 0) result += a; result += result; b = 2; } return result; 1 lg N N N lg N N2 N2 lg N

public static int power (int a, int b) { int result = 1; while (b != 0) { if (b % 2 != 0) result *= a; result *= result; b/= 2; } return result; } 1 lg N N O N lg N O N2 O N2 lg N