{"trustable":true,"prependHtml":"\u003cstyle type\u003d\"text/css\"\u003edd \u003e pre {\n display: block;\n padding: 9.5px;\n margin: 0 0 10px;\n font-size: 13px;\n line-height: 1.42857143;\n word-break: break-all;\n word-wrap: break-word;\n color: #333;\n background-color: #f5f5f5;\n border: 1px solid #ccc;\n border-radius: 4px;\n}\u003c/style\u003e","sections":[{"title":"Description","value":{"format":"HTML","content":"\u003cp\u003e\u003cimg alt\u003d\"\" border\u003d\"0\" src\u003d\"CDN_BASE_URL/5753ae489d44cb956c2a93ae7310118e?v\u003d1715575093\"\u003e\u003c/p\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\u003cdiv\u003en很大,为了避免读入耗时太多,\u003c/div\u003e\r\n\u003cdiv\u003e输入文件只有5个整数参数n, A, B, C, a1,\u003c/div\u003e\r\n\u003cdiv\u003e由上交的程序产生数列a。\u003c/div\u003e\r\n\u003cdiv\u003e下面给出pascal/C/C++的读入语句和产生序列的语句(默认从标准输入读入):\u0026nbsp;\u003c/div\u003e\r\n\u003cdiv\u003e// for pascal\u0026nbsp;\u003c/div\u003e\r\n\u003cdiv\u003ereadln(n,A,B,C,q[1]);\u0026nbsp;\u003c/div\u003e\r\n\u003cdiv\u003efor i:\u003d2 to n do q[i] :\u003d (int64(q[i-1]) * A + B) mod 100000001;\u0026nbsp;\u003c/div\u003e\r\n\u003cdiv\u003efor i:\u003d1 to n do q[i] :\u003d q[i] mod C + 1;\u0026nbsp;\u003c/div\u003e\r\n\u003cdiv\u003e\u003c/div\u003e\r\n\u003cdiv\u003e// for C/C++\u0026nbsp;\u003c/div\u003e\r\n\u003cdiv\u003escanf(\"%d%d%d%d%d\",\u0026amp;n,\u0026amp;A,\u0026amp;B,\u0026amp;C,a+1);\u0026nbsp;\u003c/div\u003e\r\n\u003cdiv\u003efor (int i\u003d2;i\u0026lt;\u003dn;i++) a[i] \u003d ((long long)a[i-1] * A + B) % 100000001;\u0026nbsp;\u003c/div\u003e\r\n\u003cdiv\u003efor (int i\u003d1;i\u0026lt;\u003dn;i++) a[i] \u003d a[i] % C + 1;\u0026nbsp;\u003c/div\u003e\r\n\u003cdiv\u003e选手可以通过以上的程序语句得到n和数列a(a的元素类型是32位整数),\u003c/div\u003e\r\n\u003cdiv\u003en和a的含义见题目描述。\u003c/div\u003e\r\n\u003cdiv\u003e\u0026nbsp;2≤n≤10000000, 0≤A,B,C,a1≤100000000\u003c/div\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\u003cp\u003e输出一个实数,表示gx期望做对的题目个数,保留三位小数。\u003c/p\u003e"}},{"title":"Sample","value":{"format":"HTML","content":"\u003ctable class\u003d\"vjudge_sample\"\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003e3 2 0 4 1\r\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e1.167\r\n【样例说明】\r\na[] \u003d {2,3,1}\r\n正确答案\tgx的答案\t做对题目\t出现概率\r\n{1,1,1}\t{1,1,1}\t3\t1/6\r\n{1,2,1}\t{1,1,2}\t1\t1/6\r\n{1,3,1}\t{1,1,3}\t1\t1/6\r\n{2,1,1}\t{1,2,1}\t1\t1/6\r\n{2,2,1}\t{1,2,2}\t1\t1/6\r\n{2,3,1}\t{1,2,3}\t0\t1/6\r\n共有6种情况,每种情况出现的概率是1/6,gx期望做对(3+1+1+1+1+0)/6 \u003d 7/6题。(相比之下,lc随机就能期望做对11/6题)\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}},{"title":"Hint","value":{"format":"HTML","content":"\u003ch3\u003eSource\u003c/h3\u003e"}}]}