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Time Limit: 2 s Memory Limit: 256 MB Total points: 100

#8624. diyiti

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杜老师怎么用 txt 写题面，这么敷衍？

diyiti.cpp/c/pas diyiti.in diyiti.out 256MB 2s

给定一个1到n的排列，P_1,P_2,...,P_n，对所有三元组(i,j,k)求P_i*P_j*P_k的和，其中1<=i,j,k<=n,(i,j)=(j,k)=(k,i)=1。

答案对2^30取模。

input

第一行一个正整数n。

接下来一行n个正整数P_1,P_2,...,P_n。

output

输出答案。

sample in

5
3 4 2 5 1

sample out

981

20%, n<=100
40%, n<=2000
100%, n<=10^5
其中10%点, n=10^5,P_i=i
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وقت الخادم: 2025-12-09 06:38:50