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PAIRSUM - Sum of Pairwise Products |
Given N non negative numbers, the task is to answer M queries.
Each query is as follows:
Given u,v you need to find the pairwise product sum (u and v are zero indexed)
auau + au+1au+1 + au+1au + au+2au+2 + au+2au+1 + au+2au + ... + avav + avav-1 + ... + avau
Input
N a0 a1 ... aN-1 M u1 v1 u2 v2 ... uM vM
Output
Print the answer for each query in a separate line.
Example
Input: 5 2 0 1 3 3 3 0 2 1 2 3 4 Output: 7 1 27
Constraints
0 <= u <= v < N
N <= 100000
M <= 100000
0 <= ai <= 1000000
Added by: | Manukranth |
Date: | 2011-09-20 |
Time limit: | 1s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ASM64 |
hide comments
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2014-06-02 16:50:39 agaurav77
AC, pay heed to Haidar Abboud's comment. |
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2014-05-30 12:22:27 GURVINDER SINGH
Easy one AC in first attempt :) |
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2014-05-18 16:03:04 P_Quantum
gud one!! |
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2014-03-29 20:51:09 Shobhit Trehan
Fast I/O and no vectors :/ |
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2014-03-27 23:42:08 RAHUL RANJAN
Brains are Awessum Last edit: 2014-03-28 13:34:11 |
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2014-03-21 19:09:51 zicowa
nice problem look at the comment of Haider Abboud you will get the solution soon i also get it from there |
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2013-12-29 21:54:00 SanchitK
@Manukranth- i have used O(M*n) algo but still it says TLE. pls tell isnt O(M*N) enough? |
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2013-07-08 12:01:23 BLANKRK
gud one....... |
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2013-06-20 17:50:01 sumit agarwal
phew!!...data types costed me 4 TLE's...long long can handle the values... |
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2013-03-15 14:28:19 Haidar Abboud
- MAKE SURE you understand what you are asked to compute. - Each query should be answered in O(1) , resulting in a total time complexity of O(N + Q). |