DSA_cpp/DP/lec10_67.cpp at main · Jashans254/DSA_cpp · GitHub

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class Solution {
    public:

    int f(int ind , int T , vector<int>&a ,  vector<vector<int>>&dp){

        if( ind ==0 ){

            return (T % a[0] == 0 );
        }
        if(dp[ind][T]!=-1) return dp[ind][T];
        int notTake = f(ind -1 , T , a,dp);

        int take = 0 ;
        if(a[ind]<=T) take = f(ind , T - a[ind] ,a,dp);

        return dp[ind][T] = take + notTake ;
    }
        int change(int amount, vector<int>& a) {

            int n = a.size();
            vector<vector<int>> dp(n, vector<int>(amount+1, 0));

            vector<int>prev(amount+1 , 0) , cur(amount +1 , 0);

            for(int T = 0 ; T <= amount;T++){
                prev[T] = ( T% a[0] == 0);
            }

            for(int ind = 1 ; ind < n; ind++){

                for(int T =  0 ; T<=amount ; T++){

                    int notTake = prev[T];

        int take = 0 ;
        if(a[ind]<=T) take = cur[T - a[ind] ];

        cur[T] = take + notTake ;

                }

                prev = cur;
            }
            return prev[ amount ];
        }
    };