@@ -24,5 +24,42 @@ function maxProductof3Numbers(arr) {
2424 // considering -ve numbers, 2 -ve on multiplication becomes +ve
2525 const p2 = arr [ 0 ] * arr [ 1 ] * arr [ n - 1 ] ;
2626
27+ // return the largest of two probablities
28+ return p1 > p2 ? p1 : p2 ;
29+ }
30+ 31+ /** The following solution is O(n) */
32+ function maxProductof3NumbersII ( arr ) {
33+ if ( ! Array . isArray ( arr ) ) {
34+ throw new Error ( 'Invalid Argument' ) ;
35+ }
36+ 37+ let firstMax = ( secondMax = thirdMax = Number . MIN_SAFE_INTEGER ) ;
38+ let firstMin = ( secondMin = Number . MAX_SAFE_INTEGER ) ;
39+ 40+ for ( let i = 0 ; i < arr . length ; i += 1 ) {
41+ if ( arr [ i ] > firstMax ) {
42+ thirdMax = secondMax ;
43+ secondMax = firstMax ;
44+ firstMax = arr [ i ] ;
45+ } else if ( arr [ i ] > secondMax ) {
46+ thirdMax = secondMax ;
47+ secondMax = arr [ i ] ;
48+ } else if ( arr [ i ] > thirdMax ) {
49+ thirdMax = arr [ i ] ;
50+ }
51+ 52+ // check for mins
53+ if ( arr [ i ] < firstMin ) {
54+ secondMin = firstMin ;
55+ firstMin = arr [ i ] ;
56+ } else if ( arr [ i ] < secondMin ) {
57+ secondMin = arr [ i ] ;
58+ }
59+ }
60+ 61+ const p1 = firstMax * secondMax * thirdMax ;
62+ const p2 = firstMin * secondMin * firstMax ;
63+ 2764 return p1 > p2 ? p1 : p2 ;
2865}
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