DSA_cpp/DP/lec10_63.cpp at main · Jashans254/DSA_cpp · GitHub

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class Solution {
    public:

    int findWays( vector<int>& num , int tar)
    {
        int n = num.size();

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

        if(num[0] == 0) prev[0] = 2;

        else prev[0]= 1 ;

        if(num[0] !=0 && num[0] <= tar ) prev[num[0]] = 1 ;

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

            for(int sum = 0 ;sum<= tar ; sum++){

                int notTake = prev[sum];
                int take = 0 ;
                if(num[ind]<=sum) take = prev[sum- num[ind]];

                cur[sum] = (notTake + take);
            }
            prev = cur;
        }

        return prev[tar];
    }

    int countPartitions(int n  , int d , vector<int> &arr){
        int totSum = 0 ;
        for(auto &it : arr) totSum +=it;

        if(totSum -d <0 || (totSum - d)%2) return false ;

        return findWays(arr , (totSum-d)/2);
    }
        int findTargetSumWays(vector<int>& nums, int target) {

            int n = nums.size();
            return countPartitions(n , target , nums);
        }
    };