Eming cup Problem D. Game of numbers
Time Limit:?0.5 seconds
Memory Limit:?512 mebibytes
Mingming loves playing with numbers, and today, someone gives him a permutation of?nn?:?P_1, P_2\ldots P_nP?1??,P?2??…P?n??.
Nannan is Mingming's friend, then he asked Mingming: if he select a number?xx?between?[l, r][l,r], and them select another number?yy?in range?(x, r](x,r], then calculate?A_xA_yA?x??A?y??. It is clear that there are many valid selections. Nannan wants to know the sum of them. As the number can be very large, you only have to output the answer module?10^9 + 710?9??+7
To make Mingming enjoy the game more, Nannan gives him?QQ?pairs of?l, rl,r. Of course, Mingming can solve this problem. But now, he wants to check if you can solve the problem.
More exactly, your task is to calculate?\sum_{l\le i\le r}\sum_{i< j\le r} A_iA_j∑?l≤i≤r??∑?i<j≤r??A?i??A?j???module?10^9 + 710?9??+7?for each?l, rl,r, where?A_1, A_2, \ldots A_nA?1??,A?2??,…A?n???is a permutation of?nn.
Input
First line is a number?nn(3\le n\le 10^53≤n≤10?5??), which means the length of sequence a.
Second line is?nn?numbers from?A_1A?1???to?A_nA?n??(1\le A_i\le 10^51≤A?i??≤10?5??, for each?i \neq ji≠j,?A_i \neq A_jA?i??≠A?j??).
Third line is a number?Q(1\le Q\le 10^5)Q(1≤Q≤10?5??)?means how many pairs of?ll?and?rr?will be chosen.
In the next?QQ?lines, the?ii-th one contians two integers?ll?and?rr?(l< rl<r), which is the?ii-th query.
Output
Output?QQ?lines of answers for each pairs query.
Examples
Sample Input
5 3 2 4 1 5 2 1 2 2 4Sample Output
6 14Note
2?times×?500000004?\equiv≡?1 (mod?10^9+710?9??+7)
前綴和
?
轉載于:https://www.cnblogs.com/sakumia/p/6507119.html
總結
以上是生活随笔為你收集整理的Eming cup Problem D. Game of numbers的全部內容,希望文章能夠幫你解決所遇到的問題。
- 上一篇: IntelliJ IDEA 建空包合并问
- 下一篇: 通过城市联动实时将地址显示到text中