Longest Arithmetic Progression | DP | The function returns true if there exist three elements in AP Assumption : set [ 0. . n - 1 ] is sorted . The code strictly implements the algorithm provided in the reference . ; One by fix every element as middle element ; Initialize i and k for the current j ; Find if there exist i and k that form AP with j as middle element
function arithmeticThree ( set , n ) { for ( let j = 1 ; j < n - 1 ; j ++ ) { let i = j - 1 , k = j + 1 ; while ( i >= 0 && k <= n - 1 ) { if ( set [ i ] + set [ k ] == 2 * set [ j ] ) return true ; ( set [ i ] + set [ k ] < 2 * set [ j ] ) ? k ++ : i -- ; } } return false ; }