Interpolatie zoeken
Gegeven een gesorteerde array van n uniform verdeelde waarden, schrijf arr[] een functie om naar een bepaald element x in de array te zoeken.
Lineair zoeken vindt het element in O(n) tijd Sprong zoeken kost O(n) tijd en Binaire zoekopdracht kost O(log n) tijd.
Het zoeken naar interpolatie is een verbetering ten opzichte van Binaire zoekopdracht voor gevallen waarin de waarden in een gesorteerde array uniform verdeeld zijn. Interpolatie construeert nieuwe datapunten binnen het bereik van een discrete set bekende datapunten. Binary Search gaat altijd naar het middelste element om te controleren. Aan de andere kant kan het zoeken naar interpolatie naar verschillende locaties gaan, afhankelijk van de waarde van de sleutel die wordt doorzocht. Als de waarde van de sleutel bijvoorbeeld dichter bij het laatste element ligt, zal het zoeken naar interpolatie waarschijnlijk beginnen aan de eindzijde.
Om de te doorzoeken positie te vinden, wordt de volgende formule gebruikt.
// Het idee van de formule is om een hogere waarde van pos terug te geven
// wanneer het te doorzoeken element dichter bij arr[hi] ligt. En
// kleinere waarde dichter bij arr[lo]arr[] ==> Array waarin elementen moeten worden doorzocht
x ==> Element waarnaar moet worden gezocht
lo ==> Beginindex in arr[]
hoi ==> Eindindex in arr[]
na = de +
Er zijn veel verschillende interpolatiemethoden en één daarvan staat bekend als lineaire interpolatie. Voor lineaire interpolatie zijn twee gegevenspunten nodig die we aannemen als (x1y1) en (x2y2) en de formule is: op punt(xy).
Dit algoritme werkt op een manier waarop we naar een woord in een woordenboek zoeken. Het interpolatiezoekalgoritme verbetert het binaire zoekalgoritme. De formule voor het vinden van een waarde is: K = > K is een constante die wordt gebruikt om de zoekruimte te verkleinen. In het geval van binair zoeken is de waarde voor deze constante: K=(laag+hoog)/2.
De formule voor pos kan als volgt worden afgeleid.
Let's assume that the elements of the array are linearly distributed.
General equation of line : y = m*x + c.
y is the value in the array and x is its index.
Now putting value of lohi and x in the equation
arr[hi] = m*hi+c ----(1)
arr[lo] = m*lo+c ----(2)
x = m*pos + c ----(3)
m = (arr[hi] - arr[lo] )/ (hi - lo)
subtracting eqxn (2) from (3)
x - arr[lo] = m * (pos - lo)
lo + (x - arr[lo])/m = pos
pos = lo + (x - arr[lo]) *(hi - lo)/(arr[hi] - arr[lo])Algoritme
De rest van het interpolatiealgoritme is hetzelfde, behalve de bovenstaande partitielogica.
- Stap1: Bereken in een lus de waarde van 'pos' met behulp van de sondepositieformule.
- Stap2: Als het een match is, retourneer dan de index van het item en sluit af.
- Stap3: Als het item kleiner is dan arr[pos], bereken dan de probepositie van de linker subarray. Anders bereken je hetzelfde in de rechter subarray.
- Stap 4: Herhaal dit totdat er een overeenkomst is gevonden of de subarray tot nul is teruggebracht.
Hieronder ziet u de implementatie van het algoritme.
// C++ program to implement interpolation // search with recursion #include using namespace std ; // If x is present in arr[0..n-1] then returns // index of it else returns -1. int interpolationSearch ( int arr [] int lo int hi int x ) { int pos ; // Since array is sorted an element present // in array must be in range defined by corner if ( lo <= hi && x >= arr [ lo ] && x <= arr [ hi ]) { // Probing the position with keeping // uniform distribution in mind. pos = lo + ((( double )( hi - lo ) / ( arr [ hi ] - arr [ lo ])) * ( x - arr [ lo ])); // Condition of target found if ( arr [ pos ] == x ) return pos ; // If x is larger x is in right sub array if ( arr [ pos ] < x ) return interpolationSearch ( arr pos + 1 hi x ); // If x is smaller x is in left sub array if ( arr [ pos ] > x ) return interpolationSearch ( arr lo pos - 1 x ); } return -1 ; } // Driver Code int main () { // Array of items on which search will // be conducted. int arr [] = { 10 12 13 16 18 19 20 21 22 23 24 33 35 42 47 }; int n = sizeof ( arr ) / sizeof ( arr [ 0 ]); // Element to be searched int x = 18 ; int index = interpolationSearch ( arr 0 n - 1 x ); // If element was found if ( index != -1 ) cout < < 'Element found at index ' < < index ; else cout < < 'Element not found.' ; return 0 ; } // This code is contributed by equbalzeeshan
C // C program to implement interpolation search // with recursion #include // If x is present in arr[0..n-1] then returns // index of it else returns -1. int interpolationSearch ( int arr [] int lo int hi int x ) { int pos ; // Since array is sorted an element present // in array must be in range defined by corner if ( lo <= hi && x >= arr [ lo ] && x <= arr [ hi ]) { // Probing the position with keeping // uniform distribution in mind. pos = lo + ((( double )( hi - lo ) / ( arr [ hi ] - arr [ lo ])) * ( x - arr [ lo ])); // Condition of target found if ( arr [ pos ] == x ) return pos ; // If x is larger x is in right sub array if ( arr [ pos ] < x ) return interpolationSearch ( arr pos + 1 hi x ); // If x is smaller x is in left sub array if ( arr [ pos ] > x ) return interpolationSearch ( arr lo pos - 1 x ); } return -1 ; } // Driver Code int main () { // Array of items on which search will // be conducted. int arr [] = { 10 12 13 16 18 19 20 21 22 23 24 33 35 42 47 }; int n = sizeof ( arr ) / sizeof ( arr [ 0 ]); int x = 18 ; // Element to be searched int index = interpolationSearch ( arr 0 n - 1 x ); // If element was found if ( index != -1 ) printf ( 'Element found at index %d' index ); else printf ( 'Element not found.' ); return 0 ; }
Java // Java program to implement interpolation // search with recursion import java.util.* ; class GFG { // If x is present in arr[0..n-1] then returns // index of it else returns -1. public static int interpolationSearch ( int arr [] int lo int hi int x ) { int pos ; // Since array is sorted an element // present in array must be in range // defined by corner if ( lo <= hi && x >= arr [ lo ] && x <= arr [ hi ] ) { // Probing the position with keeping // uniform distribution in mind. pos = lo + ((( hi - lo ) / ( arr [ hi ] - arr [ lo ] )) * ( x - arr [ lo ] )); // Condition of target found if ( arr [ pos ] == x ) return pos ; // If x is larger x is in right sub array if ( arr [ pos ] < x ) return interpolationSearch ( arr pos + 1 hi x ); // If x is smaller x is in left sub array if ( arr [ pos ] > x ) return interpolationSearch ( arr lo pos - 1 x ); } return - 1 ; } // Driver Code public static void main ( String [] args ) { // Array of items on which search will // be conducted. int arr [] = { 10 12 13 16 18 19 20 21 22 23 24 33 35 42 47 }; int n = arr . length ; // Element to be searched int x = 18 ; int index = interpolationSearch ( arr 0 n - 1 x ); // If element was found if ( index != - 1 ) System . out . println ( 'Element found at index ' + index ); else System . out . println ( 'Element not found.' ); } } // This code is contributed by equbalzeeshan
Python # Python3 program to implement # interpolation search # with recursion # If x is present in arr[0..n-1] then # returns index of it else returns -1. def interpolationSearch ( arr lo hi x ): # Since array is sorted an element present # in array must be in range defined by corner if ( lo <= hi and x >= arr [ lo ] and x <= arr [ hi ]): # Probing the position with keeping # uniform distribution in mind. pos = lo + (( hi - lo ) // ( arr [ hi ] - arr [ lo ]) * ( x - arr [ lo ])) # Condition of target found if arr [ pos ] == x : return pos # If x is larger x is in right subarray if arr [ pos ] < x : return interpolationSearch ( arr pos + 1 hi x ) # If x is smaller x is in left subarray if arr [ pos ] > x : return interpolationSearch ( arr lo pos - 1 x ) return - 1 # Driver code # Array of items in which # search will be conducted arr = [ 10 12 13 16 18 19 20 21 22 23 24 33 35 42 47 ] n = len ( arr ) # Element to be searched x = 18 index = interpolationSearch ( arr 0 n - 1 x ) if index != - 1 : print ( 'Element found at index' index ) else : print ( 'Element not found' ) # This code is contributed by Hardik Jain
C# // C# program to implement // interpolation search using System ; class GFG { // If x is present in // arr[0..n-1] then // returns index of it // else returns -1. static int interpolationSearch ( int [] arr int lo int hi int x ) { int pos ; // Since array is sorted an element // present in array must be in range // defined by corner if ( lo <= hi && x >= arr [ lo ] && x <= arr [ hi ]) { // Probing the position // with keeping uniform // distribution in mind. pos = lo + ((( hi - lo ) / ( arr [ hi ] - arr [ lo ])) * ( x - arr [ lo ])); // Condition of // target found if ( arr [ pos ] == x ) return pos ; // If x is larger x is in right sub array if ( arr [ pos ] < x ) return interpolationSearch ( arr pos + 1 hi x ); // If x is smaller x is in left sub array if ( arr [ pos ] > x ) return interpolationSearch ( arr lo pos - 1 x ); } return - 1 ; } // Driver Code public static void Main () { // Array of items on which search will // be conducted. int [] arr = new int []{ 10 12 13 16 18 19 20 21 22 23 24 33 35 42 47 }; // Element to be searched int x = 18 ; int n = arr . Length ; int index = interpolationSearch ( arr 0 n - 1 x ); // If element was found if ( index != - 1 ) Console . WriteLine ( 'Element found at index ' + index ); else Console . WriteLine ( 'Element not found.' ); } } // This code is contributed by equbalzeeshan
JavaScript < script > // Javascript program to implement Interpolation Search // If x is present in arr[0..n-1] then returns // index of it else returns -1. function interpolationSearch ( arr lo hi x ){ let pos ; // Since array is sorted an element present // in array must be in range defined by corner if ( lo <= hi && x >= arr [ lo ] && x <= arr [ hi ]) { // Probing the position with keeping // uniform distribution in mind. pos = lo + Math . floor ((( hi - lo ) / ( arr [ hi ] - arr [ lo ])) * ( x - arr [ lo ]));; // Condition of target found if ( arr [ pos ] == x ){ return pos ; } // If x is larger x is in right sub array if ( arr [ pos ] < x ){ return interpolationSearch ( arr pos + 1 hi x ); } // If x is smaller x is in left sub array if ( arr [ pos ] > x ){ return interpolationSearch ( arr lo pos - 1 x ); } } return - 1 ; } // Driver Code let arr = [ 10 12 13 16 18 19 20 21 22 23 24 33 35 42 47 ]; let n = arr . length ; // Element to be searched let x = 18 let index = interpolationSearch ( arr 0 n - 1 x ); // If element was found if ( index != - 1 ){ document . write ( `Element found at index ${ index } ` ) } else { document . write ( 'Element not found' ); } // This code is contributed by _saurabh_jaiswal < /script>
PHP // PHP program to implement $erpolation search // with recursion // If x is present in arr[0..n-1] then returns // index of it else returns -1. function interpolationSearch ( $arr $lo $hi $x ) { // Since array is sorted an element present // in array must be in range defined by corner if ( $lo <= $hi && $x >= $arr [ $lo ] && $x <= $arr [ $hi ]) { // Probing the position with keeping // uniform distribution in mind. $pos = ( int )( $lo + ((( double )( $hi - $lo ) / ( $arr [ $hi ] - $arr [ $lo ])) * ( $x - $arr [ $lo ]))); // Condition of target found if ( $arr [ $pos ] == $x ) return $pos ; // If x is larger x is in right sub array if ( $arr [ $pos ] < $x ) return interpolationSearch ( $arr $pos + 1 $hi $x ); // If x is smaller x is in left sub array if ( $arr [ $pos ] > $x ) return interpolationSearch ( $arr $lo $pos - 1 $x ); } return - 1 ; } // Driver Code // Array of items on which search will // be conducted. $arr = array ( 10 12 13 16 18 19 20 21 22 23 24 33 35 42 47 ); $n = sizeof ( $arr ); $x = 47 ; // Element to be searched $index = interpolationSearch ( $arr 0 $n - 1 $x ); // If element was found if ( $index != - 1 ) echo 'Element found at index ' . $index ; else echo 'Element not found.' ; return 0 ; #This code is contributed by Susobhan Akhuli ?>
Uitvoer
Element found at index 4
Tijdcomplexiteit: O(logboek 2 (log 2 n)) voor het gemiddelde geval en O(n) voor het slechtste geval
Complexiteit van de hulpruimte: O(1)
Een andere aanpak: -
Dit is de iteratiebenadering voor het zoeken naar interpolatie.
- Stap1: Bereken in een lus de waarde van 'pos' met behulp van de sondepositieformule.
- Stap2: Als het een match is, retourneer dan de index van het item en sluit af.
- Stap3: Als het item kleiner is dan arr[pos], bereken dan de probepositie van de linker subarray. Anders bereken je hetzelfde in de rechter subarray.
- Stap 4: Herhaal dit totdat er een overeenkomst is gevonden of de subarray tot nul is teruggebracht.
Hieronder ziet u de implementatie van het algoritme.
C++ // C++ program to implement interpolation search by using iteration approach #include using namespace std ; int interpolationSearch ( int arr [] int n int x ) { // Find indexes of two corners int low = 0 high = ( n - 1 ); // Since array is sorted an element present // in array must be in range defined by corner while ( low <= high && x >= arr [ low ] && x <= arr [ high ]) { if ( low == high ) { if ( arr [ low ] == x ) return low ; return -1 ; } // Probing the position with keeping // uniform distribution in mind. int pos = low + ((( double )( high - low ) / ( arr [ high ] - arr [ low ])) * ( x - arr [ low ])); // Condition of target found if ( arr [ pos ] == x ) return pos ; // If x is larger x is in upper part if ( arr [ pos ] < x ) low = pos + 1 ; // If x is smaller x is in the lower part else high = pos - 1 ; } return -1 ; } // Main function int main () { // Array of items on whighch search will // be conducted. int arr [] = { 10 12 13 16 18 19 20 21 22 23 24 33 35 42 47 }; int n = sizeof ( arr ) / sizeof ( arr [ 0 ]); int x = 18 ; // Element to be searched int index = interpolationSearch ( arr n x ); // If element was found if ( index != -1 ) cout < < 'Element found at index ' < < index ; else cout < < 'Element not found.' ; return 0 ; } //this code contributed by Ajay Singh
Java // Java program to implement interpolation // search with recursion import java.util.* ; class GFG { // If x is present in arr[0..n-1] then returns // index of it else returns -1. public static int interpolationSearch ( int arr [] int lo int hi int x ) { int pos ; if ( lo <= hi && x >= arr [ lo ] && x <= arr [ hi ] ) { // Probing the position with keeping // uniform distribution in mind. pos = lo + ((( hi - lo ) / ( arr [ hi ] - arr [ lo ] )) * ( x - arr [ lo ] )); // Condition of target found if ( arr [ pos ] == x ) return pos ; // If x is larger x is in right sub array if ( arr [ pos ] < x ) return interpolationSearch ( arr pos + 1 hi x ); // If x is smaller x is in left sub array if ( arr [ pos ] > x ) return interpolationSearch ( arr lo pos - 1 x ); } return - 1 ; } // Driver Code public static void main ( String [] args ) { // Array of items on which search will // be conducted. int arr [] = { 10 12 13 16 18 19 20 21 22 23 24 33 35 42 47 }; int n = arr . length ; // Element to be searched int x = 18 ; int index = interpolationSearch ( arr 0 n - 1 x ); // If element was found if ( index != - 1 ) System . out . println ( 'Element found at index ' + index ); else System . out . println ( 'Element not found.' ); } }
Python # Python equivalent of above C++ code # Python program to implement interpolation search by using iteration approach def interpolationSearch ( arr n x ): # Find indexes of two corners low = 0 high = ( n - 1 ) # Since array is sorted an element present # in array must be in range defined by corner while low <= high and x >= arr [ low ] and x <= arr [ high ]: if low == high : if arr [ low ] == x : return low ; return - 1 ; # Probing the position with keeping # uniform distribution in mind. pos = int ( low + ((( float ( high - low ) / ( arr [ high ] - arr [ low ])) * ( x - arr [ low ])))) # Condition of target found if arr [ pos ] == x : return pos # If x is larger x is in upper part if arr [ pos ] < x : low = pos + 1 ; # If x is smaller x is in lower part else : high = pos - 1 ; return - 1 # Main function if __name__ == '__main__' : # Array of items on whighch search will # be conducted. arr = [ 10 12 13 16 18 19 20 21 22 23 24 33 35 42 47 ] n = len ( arr ) x = 18 # Element to be searched index = interpolationSearch ( arr n x ) # If element was found if index != - 1 : print ( 'Element found at index' index ) else : print ( 'Element not found' )
C# // C# program to implement interpolation search by using // iteration approach using System ; class Program { // Interpolation Search function static int InterpolationSearch ( int [] arr int n int x ) { int low = 0 ; int high = n - 1 ; while ( low <= high && x >= arr [ low ] && x <= arr [ high ]) { if ( low == high ) { if ( arr [ low ] == x ) return low ; return - 1 ; } int pos = low + ( int )((( float )( high - low ) / ( arr [ high ] - arr [ low ])) * ( x - arr [ low ])); if ( arr [ pos ] == x ) return pos ; if ( arr [ pos ] < x ) low = pos + 1 ; else high = pos - 1 ; } return - 1 ; } // Main function static void Main ( string [] args ) { int [] arr = { 10 12 13 16 18 19 20 21 22 23 24 33 35 42 47 }; int n = arr . Length ; int x = 18 ; int index = InterpolationSearch ( arr n x ); if ( index != - 1 ) Console . WriteLine ( 'Element found at index ' + index ); else Console . WriteLine ( 'Element not found' ); } } // This code is contributed by Susobhan Akhuli
JavaScript // JavaScript program to implement interpolation search by using iteration approach function interpolationSearch ( arr n x ) { // Find indexes of two corners let low = 0 ; let high = n - 1 ; // Since array is sorted an element present // in array must be in range defined by corner while ( low <= high && x >= arr [ low ] && x <= arr [ high ]) { if ( low == high ) { if ( arr [ low ] == x ) { return low ; } return - 1 ; } // Probing the position with keeping // uniform distribution in mind. let pos = Math . floor ( low + ((( high - low ) / ( arr [ high ] - arr [ low ])) * ( x - arr [ low ]))); // Condition of target found if ( arr [ pos ] == x ) { return pos ; } // If x is larger x is in upper part if ( arr [ pos ] < x ) { low = pos + 1 ; } // If x is smaller x is in lower part else { high = pos - 1 ; } } return - 1 ; } // Main function let arr = [ 10 12 13 16 18 19 20 21 22 23 24 33 35 42 47 ]; let n = arr . length ; let x = 18 ; // Element to be searched let index = interpolationSearch ( arr n x ); // If element was found if ( index != - 1 ) { console . log ( 'Element found at index' index ); } else { console . log ( 'Element not found' ); }
Uitvoer
Element found at index 4
Tijdcomplexiteit: O(log2(log2 n)) voor het gemiddelde geval en O(n) voor het slechtste geval
Complexiteit van de hulpruimte: O(1)
