Could anyone give me some ideas for these problems??
# | User | Rating |
---|---|---|
1 | ecnerwala | 3648 |
2 | Benq | 3580 |
3 | orzdevinwang | 3570 |
4 | cnnfls_csy | 3569 |
5 | Geothermal | 3568 |
6 | tourist | 3565 |
7 | maroonrk | 3530 |
8 | Radewoosh | 3520 |
9 | Um_nik | 3481 |
10 | jiangly | 3467 |
# | User | Contrib. |
---|---|---|
1 | maomao90 | 174 |
2 | adamant | 164 |
2 | awoo | 164 |
4 | TheScrasse | 160 |
5 | nor | 159 |
6 | maroonrk | 156 |
7 | -is-this-fft- | 150 |
8 | SecondThread | 147 |
9 | orz | 146 |
10 | pajenegod | 145 |
Could anyone give me some ideas for these problems??
Can anyone tell me any online Judge like pc^2?? ... I want to set a contest with my inputs and outputs.
Hello everybody, help with this proof please: proof
The writer say I have to proof this:
|A1 + Aj - M | + |A2n + Ai - M| <= | A1 + A2n - M | + | Aj + Ai - M |
but for me is:
| A1 + Aj - M | + |A2n + Ai - M | >= | A1 + A2n - M | + | Aj + Ai - M |
then I reduced that:
| A1 + Aj - M | + A2n + Ai - M >= A1 + A2n - M + | Aj + Ai - M |
| A1 + Aj - M | + Ai >= A1 + | Aj + Ai - M |
then if A1 + Aj - M >= 0, so Aj + Ai - M >= 0 too, so we have:
A1 + Aj - M + Ai >= A1 + Aj + Ai - M, wich is correct.
but if A1 + Aj - M < 0, we have to make two cases
if Aj + Ai - M < 0, we have :
M - A1 - Aj + Ai >= A1 + M - Aj - Ai
Ai >= A1, which is correct
but if Aj + Ai - M >= 0, we have :
M - A1 - Aj + Ai >= A1 + Aj + Ai - M
M >= A1 + Aj, wich is not always true.
I don't know how to finish this proof, maybe for any condition is not necesary to solve this last case or I was wrong in some case.
For a better understanding this is the problem: problem:
Name |
---|