Equilibrium index of an array | Java program to find equilibrium index of an array ; function to find the equilibrium index ; initialize sum of whole array ; initialize leftsum ; Find sum of the whole array ; sum is now right sum for index i ; If no equilibrium index found , then return 0 ; Driver code
class EquilibriumIndex { int equilibrium ( int arr [ ] , int n ) { int sum = 0 ; int leftsum = 0 ; for ( int i = 0 ; i < n ; ++ i ) sum += arr [ i ] ; for ( int i = 0 ; i < n ; ++ i ) { sum -= arr [ i ] ; if ( leftsum == sum ) return i ; leftsum += arr [ i ] ; } return - 1 ; } public static void main ( String [ ] args ) { EquilibriumIndex equi = new EquilibriumIndex ( ) ; int arr [ ] = { - 7 , 1 , 5 , 2 , - 4 , 3 , 0 } ; int arr_size = arr . length ; System . out . println ( " First ▁ equilibrium ▁ index ▁ is ▁ " + equi . equilibrium ( arr , arr_size ) ) ; } }