ARTS_20200529

  public int maxProfit(int[] prices) {    if (prices.length <= 1) {      return 0;    }
    int buy = -prices[0];    int sell = 0;    for (int i = 1; i < prices.length; i++) {      buy = Math.max(buy, -prices[i]);      sell = Math.max(sell, prices[i] + buy);    }    return sell;  }

    db.getCollection(collection).aggregate([        //按照时间筛选数据        {$match: {'createdAt':{$gte:begintime,$lte:endtime}}},
        // 按照来源、类型进行分组        {            $group: {                _id: {channel: "$source", type: "$type"},                typeTotal: {$sum: 1}            }        },
        //重整数据        {            $project: {                channel: "$_id.channel",                type: "$_id.type",                typeTotal: "$typeTotal",                _id: 0            }        }    ])

@Builder(toBuilder = true)@Getter@NoArgsConstructor@AllArgsConstructor@ToStringpublic class BankResult {  private String code;
  @JsonFormat(shape = JsonFormat.Shape.STRING)  private YearMonth period;
  private String bankCode;
  private List<Item> items;
  @Builder(toBuilder = true)  @Getter  @AllArgsConstructor  @NoArgsConstructor  public static class Item {    private List<String> statementIds;
    private List<String> voucherIds;  }}
  /**   * 从bankResults获取Item中包含statementId的voucherIds.   */  private Set<String> getVoucherIds(      final String statementId,      final List<BankResult> bankResults) {    return bankResults.stream().map(        bankResult -> {          Set<String> detailIds = bankResult.getItems().stream()              .filter(                  item -> item.getStatementIds().stream().anyMatch(                      s -> s.equals(statementId)                  )              )              .map(BankResult.Item::getVoucherIds)              .collect(HashSet::new, HashSet::addAll, HashSet::addAll);          return detailIds;        }    ).collect(HashSet::new, HashSet::addAll, HashSet::addAll);  }