Statistics

Problem Statement for "DownloadingFiles"

Problem Statement

You are downloading some files from the Internet, and you want to know how long it will take until they are completely downloaded.

For each download, you are given its current speed (in KB/s) and remaining time based on that speed (in seconds). The sum of all the speeds is your total bandwidth, which remains constant and is utilized fully at all times during the downloads. This means that when files finish downloading, the newly available bandwidth is distributed among the remaining files. The way it's distributed does not affect the final answer.

For example, consider the following scenario where you are downloading two files.
1) Speed = 3 KB/s Remaining Time 57 seconds
2) Speed = 2 KB/s Remaining Time 22 seconds

After 22 seconds, the second file will finish downloading. The first file still has 35 seconds remaining, but that time is based on the original speed. The bandwidth freed up by the second file is now allocated to the first file, and its new speed is 3+2=5 KB/s. The new remaining time is: Old_Remaining_Time * Old_Speed / New_Speed = 35*3/5 = 21 seconds.

So the actual remaining time for all the files is 21+22=43 seconds.

You will be given a String[] tasks, each element of which represents a single file being downloaded. Each file is represented as two positive integers with no leading zeroes, separated by a single space. The first integer is the current download speed in KB/s and the second integer is the remaining time in seconds based on the current speed. Return a double representing the remaining time in seconds for all the downloads to finish.

Definition

Class:
DownloadingFiles
Method:
actualTime
Parameters:
String[]
Returns:
double
Method signature:
double actualTime(String[] tasks)
(be sure your method is public)

Constraints

  • tasks will contain between 1 and 50 elements, inclusive.
  • Each element of tasks will be formatted "<speed> <time>" (quotes for clarity), where <speed> is an integer between 1 and 100, inclusive, with no leading zeroes, and <time> is an integer between 1 and 10000, inclusive, with no leading zeroes.

Examples

  1. {"3 57","2 22"}

    Returns: 43.0

    The example from above.

  2. {"3 1057","2 1022"}

    Returns: 1043.0

    This is the same as the first example but all the files will take 1000 seconds more to completely download.

  3. {"25 1000","5 5000","10 5000"}

    Returns: 2500.0

    In this case, when the first file finishes downloading, we will have 25 KB/s of newly available bandwidth. We can share it between the remaining downloads however we want without affecting the final answer. Suppose that 15 KB/s goes to the second file and 10 KB/s goes to the third file. The new speeds and remaining times for those files will be: 20 KB/s and remaining time 2000 seconds 20 KB/s and remaining time 1000 secondsThose would take 1500 seconds to complete. So the answer is 1000 + 1500 = 2500.

  4. {"1 10","1 20","2 40"}

    Returns: 27.5

    For this example, suppose that all newly available bandwidth goes to the slowest task every time. When the first download finishes (after 10 seconds), the second task doubles its speed to 2, and thus halves its remaining time from (20-10=10) to 5. When the second download finishes, the third one doubles its speed, so its remaining time goes from (40-15=25) to 12.5. The total time is 10+5+12.5=27.5.

  5. {"6 88","39 7057","63 2502","45 2285","28 8749","62 3636","1 5546","49 5741"}

    Returns: 4414.542662116041

    And here is a nice random example for you.

  6. {"6 88"}

    Returns: 88.0

  7. {"39 7057","63 2502"}

    Returns: 4243.617647058823

  8. {"45 2285","28 8749","62 3636"}

    Returns: 4246.1407407407405

  9. {"1 5546","49 5741","52 7999","3 458"}

    Returns: 6706.447619047619

  10. {"62 8369","54 7503","66 8127","1 830","75 8548"}

    Returns: 8148.6511627906975

  11. {"30 4693","58 3199","71 715","29 1681","2 5606","94 7094"}

    Returns: 3886.950704225352

  12. {"83 9185","59 9351","91 3388","38 2783","6 4260","67 3117","1 4661"}

    Returns: 5701.988405797101

  13. {"94 3786","14 9853","58 6204","99 1394","55 8873","93 4263","80 3984","48 7723"}

    Returns: 4742.258780036968

  14. {"30 8949","62 850","25 2795","42 7241","48 8247","19 1956","99 5842","45 2474","52 2799"}

    Returns: 4652.6611374407585

  15. {"42 2227","5 4046","12 4209","29 3664","59 3501","9 9068","69 5315","49 3585","53 1856","51 4045"}

    Returns: 3718.94708994709

  16. {"56 2731","3 6270","81 6850","59 4183","84 1622","89 6149","1 5066","31 1842","18 6184","47 314","26 7541"}

    Returns: 4123.648484848485

  17. {"35 9788","64 1990","70 9859","71 5971","80 5542","47 7754","58 3853","28 1095","77 7285","25 1410","61 8869","43 1562"}

    Returns: 5842.660091047041

  18. {"73 6402","83 4529","57 80","82 8808","63 8810","48 8285","18 7284","68 5809","12 5694","69 1599","46 5884","99 7386","41 260"}

    Returns: 5586.429512516469

  19. {"56 3606","63 9415","17 8218","30 500","57 6148","45 3178","48 269","25 9228","87 1662","29 4954","92 8996","8 8877","96 6017","6 4066"}

    Returns: 5274.326251896813

  20. {"32 1731","26 2492","16 1368","68 291","5 9314","87 5649","3 2103","68 6639","74 8204","76 1179","28 2052","6 2621","59 6467","48 6507","82 4152"}

    Returns: 4368.56784660767

  21. {"19 6297","26 7914","33 9332","63 5858","83 2961","21 2442","88 4865","100 388","61 2617","14 9438","96 7999","67 772","66 9623","13 8007","71 3199","65 1613"}

    Returns: 4457.067720090294

  22. {"73 1751","49 5800","86 4870","32 1323","61 168","79 1275","68 9900","10 1458","65 3918","82 4106","55 7296","48 6072","64 414","70 5638","74 610","100 5398","59 5797"}

    Returns: 4003.859534883721

  23. {"69 8564","100 7464","43 12","30 850","89 27","20 6778","12 9930","95 7399","64 5656","78 5414","67 8663","29 7340","6 3003","13 828","19 510","14 619","19 7159","47 1443"}

    Returns: 5100.610565110565

  24. {"33 1099","85 5221","98 7925","91 1954","98 4579","5 6108","39 8081","52 4664","32 7882","96 5095","33 5979","63 2981","10 5034","13 1825","93 1383","92 2638","16 9619","3 2458","81 5806"}

    Returns: 4525.540174249758

  25. {"22 1693","44 6645","91 9908","22 5916","83 4399","36 8295","10 3496","59 2064","60 4933","69 2292","41 6303","24 3279","87 8387","61 1369","95 3017","80 5056","44 2692","74 8760","58 6553","27 2545"}

    Returns: 5237.236430542778

  26. {"71 9939","85 1400","22 7478","61 6529","97 515","48 5299","85 9900","41 6500","11 9224","48 3543","18 6313","38 4834","78 1452","28 6021","82 6145","97 6360","73 9804","4 7317","89 4331","45 7958","90 5064"}

    Returns: 5545.464905037159

  27. {"43 8464","46 2513","2 2480","97 2727","10 260","99 3044","59 381","35 2144","62 451","82 6677","44 1834","37 5090","30 4165","79 1997","17 2712","14 5420","2 5889","60 4694","4 3194","73 2438","57 2568","75 96"}

    Returns: 2957.5920155793574

  28. {"19 7480","84 1511","80 2699","15 1261","44 1214","30 4556","85 8688","95 5237","83 5998","98 4391","21 8609","6 2115","40 9466","86 638","23 1212","21 5638","86 2459","53 3960","70 4180","80 2593","5 5597","17 4003","39 2862"}

    Returns: 4034.263559322034

  29. {"86 6699","81 800","65 1825","45 1813","36 7264","65 7129","76 1110","14 8327","22 6798","100 494","57 940","69 4934","86 1256","3 1086","81 7967","10 7288","39 9687","45 3415","60 8002","32 5927","80 8820","38 8094","44 9144","60 1281"}

    Returns: 4546.3941267387945

  30. {"2 7519","29 9002","37 5403","59 1929","77 5724","43 5401","99 9720","68 5028","15 1552","49 6218","87 7473","59 9998","67 2280","49 4817","74 3226","35 8835","60 6867","74 7014","60 733","42 1830","76 1283","99 8502","38 8502","28 8845","82 304"}

    Returns: 5439.272727272727

  31. {"56 6593","37 3527","87 2770","44 1028","85 3066","13 1653","65 9444","33 9024","37 8571","79 7353","100 996","75 6646","72 6430","55 7824","89 120","51 9069","34 8004","31 956","86 5452","20 8032","2 1922","98 3153","89 8492","36 3295","83 3791","41 7193"}

    Returns: 5053.617489986649

  32. {"99 4411","48 109","71 1304","66 2704","1 2703","2 6096","83 7228","40 6056","82 7875","90 9684","84 5472","88 726","31 5523","54 4104","45 6108","83 2611","85 5060","32 2319","26 252","74 1356","27 137","96 1985","67 1585","32 5554","78 2335","48 9191","83 2189"}

    Returns: 3956.4377708978327

  33. {"32 3339","95 2546","50 995","53 9498","33 5776","24 4550","82 7350","43 6483","43 6269","79 127","29 9687","50 1705","29 5988","29 824","30 7651","51 2784","73 7002","69 5728","57 8631","37 5711","74 2056","91 6953","19 3320","52 9284","59 8667","85 4536","40 2812","28 5998"}

    Returns: 5164.121169916434

  34. {"77 9860","5 3959","50 1278","4 4049","76 8153","89 8166","51 1262","92 5349","82 1090","82 7733","10 1774","55 183","31 1277","57 460","74 7318","29 1719","48 5643","57 7588","89 4177","58 3320","65 273","71 9883","15 3790","13 6788","91 5720","40 7587","25 3840","82 2325","98 29"}

    Returns: 4589.220915841584

  35. {"87 3619","50 1518","45 1132","35 8849","21 1717","10 4500","61 4014","15 2810","19 599","5 3472","94 7250","22 3056","23 8602","44 8533","99 6629","46 657","51 2198","97 1612","73 886","58 8190","13 516","10 9358","25 7322","35 6715","49 4194","19 5451","58 6201","90 4483","74 2563","88 7223"}

    Returns: 4506.175847457627

  36. {"33 4559","27 9330","74 8540","15 6151","67 1564","24 6649","97 616","32 7145","63 4981","48 8910","58 4245","94 1689","33 1952","33 9049","81 5413","17 6396","80 6428","14 6488","26 4686","79 1577","20 3670","1 5947","57 5578","54 9675","53 341","43 585","28 1255","45 4800","7 3360","11 8377","53 2792"}

    Returns: 4436.912948061448

  37. {"30 4893","68 322","3 1306","64 9602","37 3912","89 9949","47 1004","53 352","64 8349","73 8996","59 1669","88 9888","86 5290","36 2592","45 1757","40 7268","40 4978","57 2108","49 4466","61 6418","46 7069","28 6456","7 9316","1 2356","27 5223","97 2618","97 826","19 1737","81 7709","8 2360","79 8283","15 8338"}

    Returns: 5266.513801756587

  38. {"58 195","71 6495","29 2614","67 726","70 80","91 5327","56 6043","94 5934","11 1936","67 3421","81 5455","80 3625","95 2801","11 8688","76 3020","30 5193","77 3047","34 1509","46 1135","20 9508","44 7097","33 3707","20 616","42 9589","91 8018","58 2471","90 1694","82 1000","36 8128","97 8145","97 7000","54 8417","61 88"}

    Returns: 4276.141188420518

  39. {"38 181","93 5221","71 2214","49 4624","69 355","87 3973","39 1521","88 2579","41 303","96 2717","51 1775","19 1905","18 610","89 5527","69 8291","45 5756","4 1623","85 7728","19 2451","69 4284","89 6271","66 3016","59 9626","89 5388","22 4606","97 2133","94 5253","100 9163","91 9275","57 5409","77 7558","41 2380","54 1028","31 5783"}

    Returns: 4682.686134852802

  40. {"82 756","63 2822","72 4072","25 8922","60 425","63 8565","72 5307","74 7822","34 434","9 5591","66 7877","32 3885","24 7586","71 9104","73 8595","63 787","55 4592","31 4870","2 1381","55 8835","80 2901","13 6581","59 5646","42 9168","13 1551","16 1997","56 3463","99 772","8 4976","56 1263","82 604","68 1805","22 1119","14 1876","27 1902"}

    Returns: 4242.897679952409

  41. {"5 8634","9 8502","88 1798","87 2175","31 8754","18 3154","97 1540","46 3626","70 3550","44 4951","35 8243","31 6648","59 3242","43 1658","60 1480","95 9883","82 8473","18 7300","8 1694","56 7527","1 3438","85 6102","5 2502","46 9268","12 6739","23 7967","45 82","38 6862","39 7173","30 9991","56 2601","82 2885","15 4470","90 1832","32 3334","66 9341"}

    Returns: 4875.671523982999

  42. {"65 1578","2 1568","99 8281","2 4607","17 3595","27 5873","37 9173","86 9158","1 9941","79 1297","99 352","36 9011","23 4250","99 6026","97 7206","81 1338","99 7503","69 1498","76 4630","93 4402","34 3341","47 2980","97 3028","54 3065","64 6625","30 7677","24 9429","33 9678","87 4173","60 9040","78 7846","1 549","30 7045","39 3691","80 7957","27 3958","39 2242"}

    Returns: 5210.930880159125

  43. {"91 4992","21 4278","60 3118","69 3810","43 3701","44 9648","18 9612","75 2102","5 1428","92 5982","55 4550","78 4771","10 1179","22 1486","79 4658","60 4226","19 77","14 677","47 9933","15 4048","95 8096","7 409","61 4087","78 9103","86 3437","94 6389","5 1461","89 6755","63 1155","23 9097","27 1198","83 5797","3 564","20 5095","95 1903","59 4163","4 6518","40 71"}

    Returns: 4804.315846403461

  44. {"7 1687","13 6046","31 9476","17 4500","81 8251","96 5035","98 7738","14 7021","42 515","91 6659","99 5708","22 2757","80 730","49 6947","11 1552","40 2740","29 8770","19 7004","56 3647","33 8099","5 1359","94 5924","28 1977","28 6611","64 3927","82 5251","11 1694","13 1239","46 9737","52 9463","5 2709","82 4246","29 546","97 7553","22 9752","85 2858","75 4377","97 1702","79 7382"}

    Returns: 5313.035379812695

  45. {"77 4339","97 533","53 1519","28 7168","92 1541","69 8945","33 9209","20 9197","10 7238","81 2767","98 2005","75 2983","93 6801","13 3138","45 3385","33 3323","44 9029","45 7202","51 6909","84 9404","64 1478","21 9996","43 6255","78 7153","14 3947","88 8959","71 639","40 995","18 3071","77 9553","3 1796","81 7167","85 7393","13 9656","84 1606","64 906","45 9524","78 5073","23 8338","78 4104"}

    Returns: 5047.290176550476

  46. {"88 2799","17 8732","84 6313","62 5604","28 7165","22 6078","59 2656","98 443","1 1262","99 8622","86 1761","69 2801","54 965","44 2440","76 233","71 2810","100 1800","70 5006","64 4009","31 2786","63 2467","71 8481","92 8725","10 8838","96 9286","4 6444","43 7800","81 4217","87 4514","92 2602","91 5454","23 192","59 5775","14 8475","95 4056","89 6518","5 4713","10 307","71 7035","92 4968","17 6303"}

    Returns: 4591.174629324547

  47. {"64 475","35 6113","66 2906","14 5699","56 4910","84 3479","49 4561","49 8508","49 5917","86 7214","90 3863","77 7527","94 9484","87 5050","64 6682","85 6738","8 8610","67 7366","71 9084","40 703","74 2029","90 829","45 2229","61 599","71 4651","1 2978","8 9885","9 4116","7 642","61 7274","98 451","92 4598","2 361","98 8189","59 1592","88 8064","12 9933","10 1688","59 900","91 2232","12 5310","63 654"}

    Returns: 4671.001278772378

  48. {"30 3808","69 1114","65 31","33 4178","82 9675","41 7317","8 7481","13 6718","8 7270","43 1436","40 6840","59 2816","83 2439","13 2550","100 9068","53 7208","23 9017","7 9199","88 1674","66 4971","52 2986","40 1909","21 569","56 7059","81 4348","8 9596","88 5349","18 4172","97 1173","4 1978","31 7648","75 6649","77 8591","68 9708","89 1211","84 3133","60 409","6 511","36 5233","90 354","18 756","53 904","22 301"}

    Returns: 4233.7807435653

  49. {"18 4454","93 2823","19 8828","97 1615","88 1721","91 2539","50 9097","82 987","100 8112","74 6127","95 379","47 1466","40 949","47 5813","22 7143","5 919","20 3860","47 1107","16 2068","27 3779","12 1135","81 7796","49 6173","48 7729","18 8091","42 9557","70 6657","45 5963","85 4690","8 4072","72 9683","1 3131","71 4095","48 2836","31 250","11 1331","24 5109","79 994","41 7634","99 5942","65 2760","96 1505","4 1305","22 9804"}

    Returns: 4327.294090909091

  50. {"98 8930","25 4244","27 5010","6 7250","12 2831","38 5583","5 9813","38 3703","88 897","1 2925","5 6990","48 3440","94 3309","53 2477","8 9706","34 1845","39 9756","70 6433","90 4733","43 8595","7 2012","70 14","54 4015","69 6408","63 652","44 1310","29 3946","69 8585","44 9667","7 7137","35 6829","5 1487","95 9226","63 8743","70 2812","78 1334","75 9549","17 328","1 9534","54 5501","30 1870","18 796","10 5022","8 281","52 498"}

    Returns: 4866.860772895712

  51. {"4 9843","76 5530","55 4209","74 3666","44 7903","14 3863","99 7411","29 2091","65 1045","75 5403","51 3118","93 6943","52 5728","84 1857","36 9046","38 434","38 4653","68 8249","72 6036","46 8141","30 336","79 9317","64 9315","4 7790","16 4686","47 3006","79 9172","46 838","58 144","94 3981","96 4874","85 1146","55 7015","51 5314","76 767","32 6451","55 9394","65 4032","30 2845","25 6302","89 698","62 1614","89 6886","12 1725","61 3942","57 3272"}

    Returns: 4764.940077821012

  52. {"26 9372","30 275","78 4839","72 4940","83 1050","83 3900","73 8126","39 9678","53 2649","11 6019","83 2689","39 84","67 2796","33 9274","35 554","64 6731","33 9157","68 1430","82 199","88 2160","46 7309","100 4527","46 3739","13 5816","54 5616","67 4068","48 8427","3 697","28 6750","10 9126","6 3730","80 6478","53 9692","20 8024","25 9326","62 8198","79 6049","18 1110","92 3137","77 7126","87 7481","93 6315","15 8145","22 2547","24 6373","66 1192","44 7992"}

    Returns: 4937.60752688172

  53. {"12 2520","54 4217","93 3908","14 3685","63 5558","99 4317","87 2391","73 7385","84 3407","69 4525","76 126","32 9002","35 9850","99 5368","86 1354","75 6484","41 8915","7 2053","24 4433","1 8899","34 168","19 6937","19 9691","71 4474","73 9581","21 802","29 1606","27 2319","23 7480","37 7984","41 2530","66 4812","19 8677","47 7526","36 9222","58 1984","64 308","54 7582","15 6458","13 7628","81 150","57 1986","55 5595","12 9111","9 7123","14 1780","28 5306","5 2746"}

    Returns: 4558.751278475128

  54. {"73 8871","71 6583","10 1100","5 2420","9 2145","47 7699","99 1483","11 3160","59 275","95 3221","15 1204","47 7322","22 3893","78 7628","66 2840","60 9749","72 4449","12 173","54 7163","10 6616","68 8664","44 4816","22 3992","88 917","93 236","50 6801","92 746","44 9056","65 9716","37 1408","36 5957","82 6678","27 8251","2 2562","95 475","57 675","82 3505","88 4238","25 4711","90 1067","15 7128","2 4496","63 3574","59 8882","47 7177","36 3385","38 5288","5 9620","51 2701"}

    Returns: 4447.767162944582

  55. {"37 4093","22 1140","79 2094","98 5428","86 7348","35 8641","8 4546","26 1473","62 6921","59 9470","68 2759","87 5675","81 6062","31 7435","12 6055","3 878","14 5654","46 6925","58 5296","37 8312","48 3306","41 1214","46 3683","38 6141","12 5237","38 5258","28 9112","42 804","81 5255","31 2196","100 3159","48 9911","91 5910","100 8175","91 2705","94 2855","81 7352","91 4902","97 501","34 3589","95 1147","77 6500","41 523","80 2202","9 2861","48 1948","15 5037","90 5888","66 2372","11 8434"}

    Returns: 4671.076667895319

  56. {"100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000","100 10000"}

    Returns: 10000.0

  57. {"3 1057", "2 1022" }

    Returns: 1043.0

  58. {"6 88", "39 7057", "63 2502", "45 2285", "28 8749", "62 3636", "1 5546", "49 5741" }

    Returns: 4414.542662116041

  59. {"3 57", "2 1001" }

    Returns: 434.6

  60. {"1 10", "2 10", "3 20", "4 20", "5 30" }

    Returns: 21.333333333333332

  61. {"2 22", "3 57", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "3 44", "2 43" }

    Returns: 43.9527027027027

  62. {"5 11", "4 11", "8 11", "3 12", "2 10", "2 15", "1 15", "91 11" }

    Returns: 11.112068965517242

  63. {"1 10", "1 20", "1 10", "1 10" }

    Returns: 12.5

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