Complexity for a reccurence relation
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If $ T(n) = sqrt{2n}T(sqrt{2n} )+ {n ^ 2} $ , what is complexity of T(n)?
Well, I let $ n = {2 ^ k} $ , $ y(k) = frac{T({2 ^ k} )}{4 ^ k} $ and I tried to resolve this recurrence by iterations methods, but I saw that it not works here. How I can find the complexity for this recurrence?
recurrence-relations
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up vote
0
down vote
favorite
If $ T(n) = sqrt{2n}T(sqrt{2n} )+ {n ^ 2} $ , what is complexity of T(n)?
Well, I let $ n = {2 ^ k} $ , $ y(k) = frac{T({2 ^ k} )}{4 ^ k} $ and I tried to resolve this recurrence by iterations methods, but I saw that it not works here. How I can find the complexity for this recurrence?
recurrence-relations
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
If $ T(n) = sqrt{2n}T(sqrt{2n} )+ {n ^ 2} $ , what is complexity of T(n)?
Well, I let $ n = {2 ^ k} $ , $ y(k) = frac{T({2 ^ k} )}{4 ^ k} $ and I tried to resolve this recurrence by iterations methods, but I saw that it not works here. How I can find the complexity for this recurrence?
recurrence-relations
If $ T(n) = sqrt{2n}T(sqrt{2n} )+ {n ^ 2} $ , what is complexity of T(n)?
Well, I let $ n = {2 ^ k} $ , $ y(k) = frac{T({2 ^ k} )}{4 ^ k} $ and I tried to resolve this recurrence by iterations methods, but I saw that it not works here. How I can find the complexity for this recurrence?
recurrence-relations
recurrence-relations
asked Nov 15 at 10:14
Daniel
166
166
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Try substituting $n$ by $2^{k+1}$ and consider $S(k)=frac{T(2^{k+1})}{2^{k+1}}$ which is $T(n)/n$ and this in turn is equal to $2frac{T(sqrt{2n})}{sqrt{2n}} + n$. By observing that $sqrt{2n}=2^{frac{k}{2}+1}$ you reduce your recurrence to a simpler one $S(k) = 2S(frac{k}{2})+2^{k+1}$. This you might find easier to solve.
Nice! It easier to solve now, thanks!
– Daniel
Nov 15 at 14:15
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
1
down vote
accepted
Try substituting $n$ by $2^{k+1}$ and consider $S(k)=frac{T(2^{k+1})}{2^{k+1}}$ which is $T(n)/n$ and this in turn is equal to $2frac{T(sqrt{2n})}{sqrt{2n}} + n$. By observing that $sqrt{2n}=2^{frac{k}{2}+1}$ you reduce your recurrence to a simpler one $S(k) = 2S(frac{k}{2})+2^{k+1}$. This you might find easier to solve.
Nice! It easier to solve now, thanks!
– Daniel
Nov 15 at 14:15
add a comment |
up vote
1
down vote
accepted
Try substituting $n$ by $2^{k+1}$ and consider $S(k)=frac{T(2^{k+1})}{2^{k+1}}$ which is $T(n)/n$ and this in turn is equal to $2frac{T(sqrt{2n})}{sqrt{2n}} + n$. By observing that $sqrt{2n}=2^{frac{k}{2}+1}$ you reduce your recurrence to a simpler one $S(k) = 2S(frac{k}{2})+2^{k+1}$. This you might find easier to solve.
Nice! It easier to solve now, thanks!
– Daniel
Nov 15 at 14:15
add a comment |
up vote
1
down vote
accepted
up vote
1
down vote
accepted
Try substituting $n$ by $2^{k+1}$ and consider $S(k)=frac{T(2^{k+1})}{2^{k+1}}$ which is $T(n)/n$ and this in turn is equal to $2frac{T(sqrt{2n})}{sqrt{2n}} + n$. By observing that $sqrt{2n}=2^{frac{k}{2}+1}$ you reduce your recurrence to a simpler one $S(k) = 2S(frac{k}{2})+2^{k+1}$. This you might find easier to solve.
Try substituting $n$ by $2^{k+1}$ and consider $S(k)=frac{T(2^{k+1})}{2^{k+1}}$ which is $T(n)/n$ and this in turn is equal to $2frac{T(sqrt{2n})}{sqrt{2n}} + n$. By observing that $sqrt{2n}=2^{frac{k}{2}+1}$ you reduce your recurrence to a simpler one $S(k) = 2S(frac{k}{2})+2^{k+1}$. This you might find easier to solve.
answered Nov 15 at 11:32
Lacramioara
32126
32126
Nice! It easier to solve now, thanks!
– Daniel
Nov 15 at 14:15
add a comment |
Nice! It easier to solve now, thanks!
– Daniel
Nov 15 at 14:15
Nice! It easier to solve now, thanks!
– Daniel
Nov 15 at 14:15
Nice! It easier to solve now, thanks!
– Daniel
Nov 15 at 14:15
add a comment |
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