我正在尝试用这段代码解决成对的hackerrank可分和问题，但是结果却是0？
dput(matadata.list)
structure(list(metaDataProperty = structure(list(EarthObservationMetaData = structure(list(
identifier = "20170127_213132_0e0e_3B_AnalyticMS", acquisitionType = "NOMINAL",
productType = "L3B", status = "ARCHIVED", downlinkedTo = structure(list(
DownlinkInformation = structure(list(acquisitionStation = structure(list(
text = "Planet Ground Station Network", .attrs = structure("urn:eop:PS:stationLocation", .Names = "codeSpace")), .Names = c("text",
".attrs")), acquisitionDate = "2017-01-27T21:31:32+00:00"), .Names = c("acquisitionStation",
"acquisitionDate"))), .Names = "DownlinkInformation"),
archivedIn = structure(list(ArchivingInformation = structure(list(
archivingCenter = structure(list(text = "Planet Archive Center",
.attrs = structure("urn:eop:PS:stationLocation", .Names = "codeSpace")), .Names = c("text",
".attrs")), archivingDate = "2017-01-27T21:31:32+00:00",
archivingIdentifier = structure(list(text = "385180",
.attrs = structure("urn:eop:PS:dmsCatalogueId", .Names = "codeSpace")), .Names = c("text",
".attrs"))), .Names = c("archivingCenter", "archivingDate",
"archivingIdentifier"))), .Names = "ArchivingInformation"),
processing = structure(list(ProcessingInformation = structure(list(
processorName = "CMO Processor", processorVersion = "4.1.4",
nativeProductFormat = "GeoTIFF"), .Names = c("processorName",
"processorVersion", "nativeProductFormat"))), .Names = "ProcessingInformation"),
license = structure(list(licenseType = "20160101 - Inc - Single User",
resourceLink = structure(c("PL EULA", "https://assets.planet.com/docs/20160101_Inc_SingleUser.txt"
), class = structure("XMLAttributes", package = "XML"), namespaces = structure(c("xlink",
"xlink"), .Names = c("http://www.w3.org/1999/xlink",
"http://www.w3.org/1999/xlink")), .Names = c("title",
"href"))), .Names = c("licenseType", "resourceLink")),
versionIsd = "1.0", pixelFormat = "16U"), .Names = c("identifier",
"acquisitionType", "productType", "status", "downlinkedTo", "archivedIn",
"processing", "license", "versionIsd", "pixelFormat"))), .Names = "EarthObservationMetaData"),
validTime = structure(list(TimePeriod = structure(list(beginPosition = "2017-01-27T21:31:32+00:00",
endPosition = "2017-01-27T21:31:32+00:00"), .Names = c("beginPosition",
"endPosition"))), .Names = "TimePeriod"), using = structure(list(
EarthObservationEquipment = structure(list(platform = structure(list(
Platform = structure(list(shortName = "PlanetScope",
serialIdentifier = "0e0e", orbitType = "LEO-SSO"), .Names = c("shortName",
"serialIdentifier", "orbitType"))), .Names = "Platform"),
instrument = structure(list(Instrument = structure(list(
shortName = "PS2"), .Names = "shortName")), .Names = "Instrument"),
sensor = structure(list(Sensor = structure(list(sensorType = "OPTICAL",
resolution = structure(list(text = "3.0000",
.attrs = structure("m", .Names = "uom")), .Names = c("text",
".attrs")), scanType = "FRAME"), .Names = c("sensorType",
"resolution", "scanType"))), .Names = "Sensor"),
acquisitionParameters = structure(list(Acquisition = structure(list(
orbitDirection = "DESCENDING", incidenceAngle = structure(list(
text = "8.072969e-02", .attrs = structure("deg", .Names = "uom")), .Names = c("text",
".attrs")), illuminationAzimuthAngle = structure(list(
text = "7.610387e+01", .attrs = structure("deg", .Names = "uom")), .Names = c("text",
".attrs")), illuminationElevationAngle = structure(list(
text = "4.649194e+01", .attrs = structure("deg", .Names = "uom")), .Names = c("text",
".attrs")), azimuthAngle = structure(list(text = "1.242074e+01",
.attrs = structure("deg", .Names = "uom")), .Names = c("text",
".attrs")), spaceCraftViewAngle = structure(list(
text = "5.692807e-02", .attrs = structure("deg", .Names = "uom")), .Names = c("text",
".attrs")), acquisitionDateTime = "2017-01-27T21:31:32+00:00"), .Names = c("orbitDirection",
"incidenceAngle", "illuminationAzimuthAngle", "illuminationElevationAngle",
"azimuthAngle", "spaceCraftViewAngle", "acquisitionDateTime"
))), .Names = "Acquisition")), .Names = c("platform",
"instrument", "sensor", "acquisitionParameters"))), .Names = "EarthObservationEquipment"),
target = structure(list(Footprint = structure(list(multiExtentOf = structure(list(
MultiSurface = structure(list(surfaceMembers = structure(list(
Polygon = structure(list(outerBoundaryIs = structure(list(
LinearRing = structure(list(coordinates = "175.446585079397,-37.7068873856657 175.446633607572,-37.7045627724835 175.46731776545,-37.6311749428137 175.468010520596,-37.6311839417076 175.75989021492,-37.6819836599337 175.759889856814,-37.6820051679817 175.739424097003,-37.757826933992 175.739359440859,-37.7578262423109 175.446585079397,-37.7068873856657"), .Names = "coordinates")), .Names = "LinearRing"),
.attrs = structure("EPSG:4326", .Names = "srsName")), .Names = c("outerBoundaryIs",
".attrs"))), .Names = "Polygon"), .attrs = structure("EPSG:4326", .Names = "srsName")), .Names = c("surfaceMembers",
".attrs"))), .Names = "MultiSurface"), centerOf = structure(list(
Point = structure(list(pos = "175.603162359 -37.6944367036",
.attrs = structure("EPSG:4326", .Names = "srsName")), .Names = c("pos",
".attrs"))), .Names = "Point"), geographicLocation = structure(list(
topLeft = structure(list(latitude = "-37.6311749428",
longitude = "175.446585079"), .Names = c("latitude",
"longitude")), topRight = structure(list(latitude = "-37.6311749428",
longitude = "175.759890215"), .Names = c("latitude",
"longitude")), bottomRight = structure(list(latitude = "-37.757826934",
longitude = "175.759890215"), .Names = c("latitude",
"longitude")), bottomLeft = structure(list(latitude = "-37.757826934",
longitude = "175.446585079"), .Names = c("latitude",
"longitude"))), .Names = c("topLeft", "topRight", "bottomRight",
"bottomLeft"))), .Names = c("multiExtentOf", "centerOf",
"geographicLocation"))), .Names = "Footprint"), resultOf = structure(list(
EarthObservationResult = structure(list(product = structure(list(
ProductInformation = structure(list(fileName = "20170127_213132_0e0e_3B_AnalyticMS.tif",
productFormat = "GeoTIFF", spatialReferenceSystem = structure(list(
epsgCode = "32760", geodeticDatum = "WGS_1984",
projection = "WGS 84 / UTM zone 60S", projectionZone = "160"), .Names = c("epsgCode",
"geodeticDatum", "projection", "projectionZone"
)), resamplingKernel = "CC", numRows = "4565",
numColumns = "9194", numBands = "4", rowGsd = "3.0",
columnGsd = "3.0", radiometricCorrectionApplied = "true",
geoCorrectionLevel = "Precision Geocorrection",
elevationCorrectionApplied = "FineDEM", atmosphericCorrectionApplied = "false"), .Names = c("fileName",
"productFormat", "spatialReferenceSystem", "resamplingKernel",
"numRows", "numColumns", "numBands", "rowGsd", "columnGsd",
"radiometricCorrectionApplied", "geoCorrectionLevel",
"elevationCorrectionApplied", "atmosphericCorrectionApplied"
))), .Names = "ProductInformation"), mask = structure(list(
MaskInformation = structure(list(type = "UNUSABLE DATA",
format = "RASTER", referenceSystemIdentifier = structure(list(
text = "32760", .attrs = structure("EPSG", .Names = "codeSpace")), .Names = c("text",
".attrs")), fileName = "20170127_213132_0e0e_3B_AnalyticMS_DN_udm.tif"), .Names = c("type",
"format", "referenceSystemIdentifier", "fileName"
))), .Names = "MaskInformation"), cloudCoverPercentage = structure(list(
text = "0.01", .attrs = structure("percentage", .Names = "uom")), .Names = c("text",
".attrs")), cloudCoverPercentageQuotationMode = "AUTOMATIC",
unusableDataPercentage = structure(list(text = "0.0",
.attrs = structure("percentage", .Names = "uom")), .Names = c("text",
".attrs")), bandSpecificMetadata = structure(list(
bandNumber = "1", comment = NULL, radiometricScaleFactor = "0.01",
comment = NULL, reflectanceCoefficient = "2.21386105481e-05"), .Names = c("bandNumber",
"comment", "radiometricScaleFactor", "comment", "reflectanceCoefficient"
)), bandSpecificMetadata = structure(list(bandNumber = "2",
comment = NULL, radiometricScaleFactor = "0.01",
comment = NULL, reflectanceCoefficient = "2.31474175457e-05"), .Names = c("bandNumber",
"comment", "radiometricScaleFactor", "comment", "reflectanceCoefficient"
)), bandSpecificMetadata = structure(list(bandNumber = "3",
comment = NULL, radiometricScaleFactor = "0.01",
comment = NULL, reflectanceCoefficient = "2.60208594123e-05"), .Names = c("bandNumber",
"comment", "radiometricScaleFactor", "comment", "reflectanceCoefficient"
)), bandSpecificMetadata = structure(list(bandNumber = "4",
comment = NULL, radiometricScaleFactor = "0.01",
comment = NULL, reflectanceCoefficient = "3.83481925626e-05"), .Names = c("bandNumber",
"comment", "radiometricScaleFactor", "comment", "reflectanceCoefficient"
))), .Names = c("product", "mask", "cloudCoverPercentage",
"cloudCoverPercentageQuotationMode", "unusableDataPercentage",
"bandSpecificMetadata", "bandSpecificMetadata", "bandSpecificMetadata",
"bandSpecificMetadata"))), .Names = "EarthObservationResult"),
.attrs = structure(c("http://schemas.planet.com/ps/v1/planet_product_metadata_geocorrected_level http://schemas.planet.com/ps/v1/planet_product_metadata_geocorrected_level.xsd",
"1.2.1", "1.0"), class = structure("XMLAttributes", package = "XML"), namespaces = structure(c("xsi",
"", ""), .Names = c("http://www.w3.org/2001/XMLSchema-instance",
"", "")), .Names = c("schemaLocation", "version", "planet_standard_product_version"
))), .Names = c("metaDataProperty", "validTime", "using",
"target", "resultOf", ".attrs"))每个div(6,3, [1, 3, 2, 6, 1, 2]);
function div(n, k, ar) {
var sum = 0;
ar.forEach( (el, index) => {
ar.forEach( (elem, indexS) => {
console.log((index < indexS) && (el + elem % k === 0));
if((index < indexS) && (el + elem % k === 0)) {
sum++;
}
})
})
console.log(sum);
}
都在执行其工作（已通过forEach进行了检查），但结果却始终为0？
任何人都可以提供帮助，非常感谢。
答案 0 :(得分：1)
在（el + elem）上检查操作顺序，
function div(n,k,ar){
var sum = 0;
ar.forEach((ai, ii)=> {
ar.forEach((aj, jj)=> {
let isDiv = (ii < jj) && ((ai + aj) % k === 0);
// console.log('isDiv',isDiv);
if(isDiv){
sum ++;
}
})
})
return sum;
}
let sum = div(6,3, [1, 3, 2, 6, 1, 2]);
console.log(sum);
答案 1 :(得分：1)
％的优先级更高，因此请使用方括号
Change el + elem % k to (el + elem) % k
答案 2 :(得分：1)
这里的问题是您的if语句。通过检查console.log，条件始终返回false，因此从不应用sum ++。我添加了一些评论，希望对您有所帮助！
div(6,3, [1, 3, 2, 6, 1, 2]);
function div(n,k,ar){
var sum = 0;
ar.forEach((el, index)=> {
ar.forEach((elem, indexS)=> {
console.log((index < indexS) && (el + elem % k === 0)); // this line is always false
if((index < indexS) && (el + elem % k === 0)){ // meaning this condition is never true
sum ++; // will never be called
}
})
})
console.log(sum); // returns 0, because value is never incremented
}