Count number of ways to cover a distance | Function returns count of ways to cover ' dist ' ; Initialize base values . There is one way to cover 0 and 1 distances and two ways to cover 2 distance ; Fill the count array in bottom up manner ; Driver Code
< ? php function printCountDP ( $ dist ) { $ count = array ( ) ; $ count [ 0 ] = 1 ; $ count [ 1 ] = 1 ; $ count [ 2 ] = 2 ; for ( $ i = 3 ; $ i <= $ dist ; $ i ++ ) $ count [ $ i ] = $ count [ $ i - 1 ] + $ count [ $ i - 2 ] + $ count [ $ i - 3 ] ; return $ count [ $ dist ] ; } $ dist = 4 ; echo printCountDP ( $ dist ) ; ? >