Placering af et element efter stabil sortering
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Produktion
#practiceLinkDiv { display: ingen !important; } Givet et array af heltal, som kan indeholde duplikerede elementer, et element i denne array er givet til os, er vi nødt til at fortælle den endelige position af dette element i arrayet, hvis en stabil sorteringsalgoritme anvendes.
Eksempler:
Input : arr[] = [3 4 3 5 2 3 4 3 1 5] index = 5 Output : 4 Element initial index – 5 (third 3) After sorting array by stable sorting algorithm we get array as shown below [1(8) 2(4) 3(0) 3(2) 3(5) 3(7) 4(1) 4(6) 5(3) 5(9)] with their initial indices shown in parentheses next to them Element's index after sorting = 4Recommended Practice Stabil sortering og position Prøv det!
En nem måde at løse dette problem på er at bruge en hvilken som helst stabil sorteringsalgoritme som Indsættelsessortering Sort går osv. og derefter få det nye indeks for givet element, men vi kan løse dette problem uden at sortere arrayet.
Som et elements position i et sorteret array bestemmes kun af de elementer, der er mindre end et givet element. Vi tæller alle array-elementer, der er mindre end et givet element, og for de elementer, der er lig med givne elementelementer, der forekommer før givne elementers indeks, vil det blive inkluderet i antallet af mindre elementer, hvilket vil sikre stabiliteten af resultatets indeks.
Enkel kode til at implementere ovenstående tilgang er implementeret nedenfor:
C++ // C++ program to get index of array element in // sorted array #include using namespace std ; // Method returns the position of arr[idx] after // performing stable-sort on array int getIndexInSortedArray ( int arr [] int n int idx ) { /* Count of elements smaller than current element plus the equal element occurring before given index*/ int result = 0 ; for ( int i = 0 ; i < n ; i ++ ) { // If element is smaller then increase // the smaller count if ( arr [ i ] < arr [ idx ]) result ++ ; // If element is equal then increase count // only if it occurs before if ( arr [ i ] == arr [ idx ] && i < idx ) result ++ ; } return result ; } // Driver code to test above methods int main () { int arr [] = { 3 4 3 5 2 3 4 3 1 5 }; int n = sizeof ( arr ) / sizeof ( arr [ 0 ]); int idxOfEle = 5 ; cout < < getIndexInSortedArray ( arr n idxOfEle ); return 0 ; }
Java // Java program to get index of array // element in sorted array class ArrayIndex { // Method returns the position of // arr[idx] after performing stable-sort // on array static int getIndexInSortedArray ( int arr [] int n int idx ) { /* Count of elements smaller than current element plus the equal element occurring before given index*/ int result = 0 ; for ( int i = 0 ; i < n ; i ++ ) { // If element is smaller then // increase the smaller count if ( arr [ i ] < arr [ idx ] ) result ++ ; // If element is equal then increase // count only if it occurs before if ( arr [ i ] == arr [ idx ] && i < idx ) result ++ ; } return result ; } // Driver code to test above methods public static void main ( String [] args ) { int arr [] = { 3 4 3 5 2 3 4 3 1 5 }; int n = arr . length ; int idxOfEle = 5 ; System . out . println ( getIndexInSortedArray ( arr n idxOfEle )); } } // This code is contributed by Raghav sharma
Python3 # Python program to get index of array element in # sorted array # Method returns the position of arr[idx] after # performing stable-sort on array def getIndexInSortedArray ( arr n idx ): # Count of elements smaller than current # element plus the equal element occurring # before given index result = 0 for i in range ( n ): # If element is smaller then increase # the smaller count if ( arr [ i ] < arr [ idx ]): result += 1 # If element is equal then increase count # only if it occurs before if ( arr [ i ] == arr [ idx ] and i < idx ): result += 1 return result ; # Driver code to test above methods arr = [ 3 4 3 5 2 3 4 3 1 5 ] n = len ( arr ) idxOfEle = 5 print ( getIndexInSortedArray ( arr n idxOfEle )) # Contributed by: Afzal Ansari
C# // C# program to get index of array // element in sorted array using System ; class ArrayIndex { // Method returns the position of // arr[idx] after performing stable-sort // on array static int getIndexInSortedArray ( int [] arr int n int idx ) { /* Count of elements smaller than current element plus the equal element occurring before given index*/ int result = 0 ; for ( int i = 0 ; i < n ; i ++ ) { // If element is smaller then // increase the smaller count if ( arr [ i ] < arr [ idx ]) result ++ ; // If element is equal then increase // count only if it occurs before if ( arr [ i ] == arr [ idx ] && i < idx ) result ++ ; } return result ; } // Driver code to test above methods public static void Main () { int [] arr = { 3 4 3 5 2 3 4 3 1 5 }; int n = arr . Length ; int idxOfEle = 5 ; Console . WriteLine ( getIndexInSortedArray ( arr n idxOfEle )); } } // This code is contributed by vt_m
PHP // PHP program to get index of // array element in sorted array // Method returns the position of // arr[idx] after performing // stable-sort on array function getIndexInSortedArray ( $arr $n $idx ) { /* Count of elements smaller than current element plus the equal element occurring before given index */ $result = 0 ; for ( $i = 0 ; $i < $n ; $i ++ ) { // If element is smaller then // increase the smaller count if ( $arr [ $i ] < $arr [ $idx ]) $result ++ ; // If element is equal then // increase count only if // it occurs before if ( $arr [ $i ] == $arr [ $idx ] and $i < $idx ) $result ++ ; } return $result ; } // Driver Code $arr = array ( 3 4 3 5 2 3 4 3 1 5 ); $n = count ( $arr ); $idxOfEle = 5 ; echo getIndexInSortedArray ( $arr $n $idxOfEle ); // This code is contributed by anuj_67. ?>
JavaScript < script > // JavaScript program to get index of array // element in sorted array // Method returns the position of // arr[idx] after performing stable-sort // on array function getIndexInSortedArray ( arr n idx ) { /* Count of elements smaller than current element plus the equal element occurring before given index*/ let result = 0 ; for ( let i = 0 ; i < n ; i ++ ) { // If element is smaller then // increase the smaller count if ( arr [ i ] < arr [ idx ]) result ++ ; // If element is equal then increase // count only if it occurs before if ( arr [ i ] == arr [ idx ] && i < idx ) result ++ ; } return result ; } // Driver Code let arr = [ 3 4 3 5 2 3 4 3 1 5 ]; let n = arr . length ; let idxOfEle = 5 ; document . write ( getIndexInSortedArray ( arr n idxOfEle )); // This code is contributed by code_hunt. < /script>
Produktion
4
Tidskompleksitet: På) hvor n er størrelsen af arrayet.
Hjælpeplads: O(1)
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