01 背包

void bag01(int cost,int weight)
{
 for(i=v;i>=cost;i--)
  if(dp[i]<dp[i-cost]+weight)
   dp[i]=dp[i-cost]+weight;
}

完全背包

void complete(int cost,int weight)
{
 for(i=cost;i<=v;i++)
  if(dp[i]<dp[i-cost]+weight)
   dp[i]=dp[i-cost]+weight;
}

多重背包

void multiply(int cost,int weight,int amount)
{
 if(cost*amount>=v)
  complete(cost,weight);
 else{
  k=1;
  while(k<amount){
   bag01(k*cost,k*weight);
   amount-=k;
   k+=k;
  }
  bag01(cost*amount,weight*amount);
 }
}

一、解析json对象

表结构信息对象,json格式，名称为tableObj
  *  {
  *   "tableName":"t_res",                              //表名称
  *   "columnInfo":[           //字段信息
  *            {
  *           "columnName":"id",            //字段名
  *           "dataTypeName":"varchar",     //字段类型
  *           "isKey":true,                 //是否为主键，true代表是主键，false代表不是
  *           "isAutoIncrement":true,       //是否自增，true代表自增，false代表不自增
  *           "isNull":0,                   //是否为空，1代表可以为空，0代表不能为空
  *           "precision":5,                //精度
  *           "defaultValue":"10"           //默认值
  *           "scale":2                     //小数位数         
  *          }
  *           ]
  *  }

try{
   String name = tableObj.get("tableName").toString();                //获得表名
   JSONArray columnInfo = tableObj.getJSONArray("columnInfo");        //获得字段描述json数组
   int size = columnInfo.length();                                    //json数组长度
   for(int i=0;i<size;i++){
    JSONObject info=columnInfo.getJSONObject(i);
    String cloumn = info.getString("columnName");                  //获取字段名
    String dataType = info.getString("dataTypeName");              //获取字段类型
    boolean isKey = info.getBoolean("isKey");                      //获取字段是否为主键
    boolean isAutoIncrement = info.getBoolean("isAutoIncrement");  //获取字段是否自增
    int isNull = info.getInt("isNull");                            //获取字段是否为空
    int precision = info.getInt("precision");                      //获取字段类型精度
    String defaultValue = info.getString("defaultValue");          //获取字段默认值

}

二、封装json对象

 /**
  * 根据表名获取表结构信息
  * @param tableName　表名
  * @return 表结构信息对象 Json格式
  *  {
  *   "tableName":"t_res",                              //表名称
  *   "columnInfo":[           //字段信息
  *            {
  *           "columnName":"id",            //字段名
  *           "dataTypeName":"varchar",     //字段类型
  *           "isKey":true,                 //是否为主键，true代表是主键，false代表不是
  *           "isAutoIncrement":true,       //是否自增，true代表自增，false代表不自增
  *           "isNull":0,                   //是否为空，1代表可以为空，0代表不能为空
  *           "precision":5,                //精度
  *           "defaultValue":"10"           //默认值
  *           "scale":2                     //小数位数         
  *          }
  *           ]
  *  } 
  */    

  JSONObject tableInfoObj = new JSONObject();
  StringBuffer sb = new StringBuffer();  

  sb.append("{"+"'tableName':"+tableName+","+"'columnInfo':"+"[");

  sb.append("{"+"'columnName':"+"'"+cloumn+"'"+","
      +"'dataTypeName':"+"'"+dataType+"'"+","
      +"'isKey':"+isKey+","
      +"'precision':"+precision+","
      +"'defaultValue':"+"'"+defaultValue+"'"+","
      +"'isNull':"+isNull+","
      +"'isAutoIncrement':"+autoIncrement+","
      +"'scale':"+scale+"}"+","); 

   sb.deleteCharAt(sb.length()-1);
   sb.append("]");
   sb.append("}");                                 //json字符串到此完成  
   System.out.println(sb.toString());
   tableInfoObj = new JSONObject(sb.toString());   //将json字符串转化为jsonObject对象

   return tableInfoObj;

01 背包

void bag01(int cost,int weight)
{
 for(i=v;i>=cost;i--)
  if(dp[i]<dp[i-cost]+weight)
   dp[i]=dp[i-cost]+weight;
}

完全背包

void complete(int cost,int weight)
{
 for(i=cost;i<=v;i++)
  if(dp[i]<dp[i-cost]+weight)
   dp[i]=dp[i-cost]+weight;
}

多重背包

void multiply(int cost,int weight,int amount)
{
 if(cost*amount>=v)
  complete(cost,weight);
 else{
  k=1;
  while(k<amount){
   bag01(k*cost,k*weight);
   amount-=k;
   k+=k;
  }
  bag01(cost*amount,weight*amount);
 }
}