30DAYS DSA
ROADMAP
Swi pef ormor e>
DAY2 Ar r a ys
Sor t012 Di f f i cul t y–Medi um Gi v ena na r r a ycons i s t i ngonl yof0’ s ,1 ’ sa nd 2 ’ s .Sor tt hem wi t houtus i nga nys or t i nga l gor i t hm. Comeupwi t haonepa s sa l gor i t hm us i ng onl ycons t a ntex t r as pa ce.
Ex a mpl e I nput :nums=[ 2, 0, 2, 1 , 1 , 0] Out put :[ 0, 0, 1 , 1 , 2, 2]
Pr obl em l i nk
3Sum Di f f i cul t y–Medi um Gi v ena ni nt egera r r a ynums ,r et ur na l lt he t r i pl et s[ nums [ i ] ,nums [ j ] ,nums [ k ] ]s ucht ha t i! =j ,i! =k ,a ndj! =k ,a ndnums [ i ]+nums [ j ] +nums [ k ]==0. Not i cet ha tt hes ol ut i ons etmus tnotcont a i ndupl i ca t et r i pl et s .
Ex a mpl e I nput :nums=[ 1 , 0, 1 , 2, 1 , 4] Out put :[ [ 1 , 1 , 2] , [ 1 , 0, 1 ] ] Expl anat i on: nums [ 0]+nums [ 1 ]+nums [ 2]=( 1 )+0+1=0. nums [ 1 ]+nums [ 2]+nums [ 4]=0+1+( 1 )=0. nums [ 0]+nums [ 3]+nums [ 4]=( 1 )+2+( 1 )=0. Thedi s t i nctt r i pl et sa r e[ 1 , 0, 1 ]a nd[ 1 , 1 , 2] . Not i cet ha tt heor deroft heout puta ndt heor der oft het r i pl et sdoesnotma t t er .
Pr obl em l i nk
NextPer mut at i on Di f f i cul t y–Medi um Gi v ena na r r a yofi nt eger snums ,f i ndt henext per mut a t i onofnums . Thenextper mut a t i onofa na r r a yofi nt eger si s t henextl exi cogr a phi ca l l ygr ea t erper mut a t i onof i t si nt eger .I fs ucha r r a ngementi snotpos s i bl e, t hea r r a ymus tber ea r r a ngeda st hel owes t pos s i bl eor der( i . e. ,s or t edi na s cendi ngor der ) .
Ex a mpl e: I nput :nums=[ [ 1 , 2, 3] Out put :[ 1 , 3 , 2]
Ex a mpl e2: I nput :nums=[ 3 , 2, 1 ] Out put :[ 1 , 2, 3]
Pr obl em l i nk
CountofSmal l erNumber s Af t erSel f Di f f i cul t y–Har d Gi v ena ni nt egera r r a ynums ,r et ur na ni nt eger a r r a ycount swher ecount s [ i ]i st henumberof s ma l l erel ement st ot her i ghtofnums [ i ] .
Ex a mpl e I nput :nums=[ [ 5, 2, 6, 1 ] Out put :[ 2, 1 , 1 , 0] Expl anat i on: T ot her i ghtof5t her ea r e2s ma l l erel ement s( 2 a nd1 ) . T ot her i ghtof2t her ei sonl y1s ma l l erel ement ( 1 ) . T ot her i ghtof6t her ei s1s ma l l erel ement( 1 ) . T ot her i ghtof1t her ei s0s ma l l erel ement .
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