| CSC300: PerformanceOfArrays *2 [6/13] | |
01 |
public void append(double item) { if (N == a.length) resize(2*N); a[N] = item; N += 1; } |
Output
00 00 01 00 01 02 03 00 01 02 03 04 05 06 07 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 Elapsed count f( 512): 1,023: 2.002 [ 0.000 : NaN] Elapsed count f( 1,024): 2,047: 2.001 [ 0.000 : NaN] Elapsed count f( 2,048): 4,095: 2.000 [ 0.000 : NaN] Elapsed count f( 4,096): 8,191: 2.000 [ 0.000 : NaN] Elapsed count f( 8,192): 16,383: 2.000 [ 0.000 : NaN] Elapsed count f( 16,384): 32,767: 2.000 [ 0.001 : Infinity] Elapsed count f( 32,768): 65,535: 2.000 [ 0.003 : 3.000] Elapsed count f( 65,536): 131,071: 2.000 [ 0.007 : 2.333] Elapsed count f( 131,072): 262,143: 2.000 [ 0.002 : 0.286] Elapsed count f( 262,144): 524,287: 2.000 [ 0.003 : 1.500] Elapsed count f( 524,288): 1,048,575: 2.000 [ 0.007 : 2.333] Elapsed count f( 1,048,576): 2,097,151: 2.000 [ 0.015 : 2.143] Elapsed count f( 2,097,152): 4,194,303: 2.000 [ 0.028 : 1.867] Elapsed count f( 4,194,304): 8,388,607: 2.000 [ 0.043 : 1.536] Elapsed count f( 8,388,608): 16,777,215: 2.000 [ 0.055 : 1.279] Elapsed count f( 16,777,216): 33,554,431: 2.000 [ 0.147 : 2.673] Elapsed count f( 33,554,432): 67,108,863: 2.000 [ 0.360 : 2.449] Elapsed count f( 67,108,864): 134,217,727: 2.000 [ 0.597 : 1.658] Average delta: 2.000
N appends in linear time
Each time we resize: constant appends double
Each append is amortized constant time