8张图带你分析Redis与MySQL数据一致性问题

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(n-1) * (n-2) * ... * 1= n * (n-1)!"}]},{"type":"text","text":";"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"那么我们可以用一个递归函数解决问题。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"static long jiecheng(int n)\n{\n\tif(n==1||n==0)return 1;\n\telse {\n\t return n*jiecheng(n-1);\n\t}\n}"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" 这样每输入求一次需要执行"},{"type":"codeinline","content":[{"type":"text","text":"n"}]},{"type":"text","text":"次。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"问题2："}]},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"输入t组数据(可能成百上千)，每组一个xi(xi<20),求"},{"type":"codeinline","content":[{"type":"text","text":"xi！"}]},{"type":"text","text":"；"}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"分析2"},{"type":"text","text":"："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"如果使用"},{"type":"codeinline","content":[{"type":"text","text":"递归"}]},{"type":"text","text":",输入t组数据，每次输入为xi，那么每次都要执行次数为："}]}]}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/c3/c323b51171ffe5cc8b0d86ab2de5df4b.png","alt":null,"title":"","style":[{"key":"width","value":"50%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"当每次输入的Xi过大或者t过大都会造成不小的负担！时间复杂度为"},{"type":"text","marks":[{"type":"strong"}],"text":"O(n2)"}]},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"那么能否换个思想的。没错、是"},{"type":"codeinline","content":[{"type":"text","text":"打表"}]},{"type":"text","text":"。打表常用于ACM算法中，常用于解决多组输入输出、图论搜索结果、路径储存问题。那么，对于这个求阶乘。我们只需要申请一个数组，按照编号从前往后将在需求的数存到数组中，后面再取得时候直接输出数组值就可以，思想很明确吧:"}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"import java.util.Scanner;\npublic class test {\npublic static void main(String[] args) {\n\t// TODO Auto-generated method stub\n\tScanner sc=new Scanner(System.in);\n\tint t=sc.nextInt();\n\tlong jiecheng[]=new long[21];\n\tjiecheng[0]=1;\n\tfor(int i=1;i<21;i++)\n\t{\n\t\tjiecheng[i]=jiecheng[i-1]*i;\n\t}\n for(int 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