Maximum sum bitonic subarray | function to find the maximum sum bitonic subarray ; ' msis [ ] ' to store the maximum sum increasing subarray up to each index of ' arr ' from the beginning ' msds [ ] ' to store the maximum sum decreasing subarray from each index of ' arr ' up to the end ; to store the maximum sum bitonic subarray ; building up the maximum sum increasing subarray for each array index ; building up the maximum sum decreasing subarray for each array index ; for each array index , calculating the maximum sum of bitonic subarray of which it is a part of ; if true , then update ' max ' bitonic subarray sum ; required maximum sum ; Driver Code
function maxSumBitonicSubArr ( arr , n ) { let msis = new Array ( n ) ; msis . fill ( 0 ) ; let msds = new Array ( n ) ; msds . fill ( 0 ) ; let max_sum = Number . MIN_VALUE ; msis [ 0 ] = arr [ 0 ] ; for ( let i = 1 ; i < n ; i ++ ) if ( arr [ i ] > arr [ i - 1 ] ) msis [ i ] = msis [ i - 1 ] + arr [ i ] ; else msis [ i ] = arr [ i ] ; msds [ n - 1 ] = arr [ n - 1 ] ; for ( let i = n - 2 ; i >= 0 ; i -- ) if ( arr [ i ] > arr [ i + 1 ] ) msds [ i ] = msds [ i + 1 ] + arr [ i ] ; else msds [ i ] = arr [ i ] ; for ( let i = 0 ; i < n ; i ++ ) if ( max_sum < ( msis [ i ] + msds [ i ] - arr [ i ] ) ) max_sum = msis [ i ] + msds [ i ] - arr [ i ] ; return max_sum ; } let arr = [ 5 , 3 , 9 , 2 , 7 , 6 , 4 ] ; let n = arr . length ; document . write ( " " + maxSumBitonicSubArr ( arr , n ) ) ;