Competitive-programing/1031. Maximum Sum of Two Non-Overlapping Subarrays at main · eyuuab/Competitive-programing · GitHub

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class Solution {
public:
    int helper(vector<int>& nums, int x, int y){
        int n = nums.size();
        vector<int> dp1(n, 0);
        int s1 = 0;
        for(int i=0; i<n; i++){
            if(i < x-1)
                s1 += nums[i];
            else if(i == x-1){
                s1 += nums[i];
                dp1[i] = s1;
            }
            else{
                s1 = s1 + nums[i] - nums[i - x];
                dp1[i] = max(dp1[i-1], s1);
            }
        }
        vector<int> dp2(n, 0);
        int s2 = 0;
        for(int i=n-1; i>=0; i--){
            if(y + i > n)
                s2 += nums[i];
            else if(y + i == n){
                s2 += nums[i];
                dp2[i] = s2;
            }
            else{
                s2 = s2 + nums[i] - nums[i + y];
                dp2[i] = max(dp2[i+1], s2);
            }
        }
        int max_sum = 0, i = x - 1;
        while(i + y < n){
            if(dp1[i]+dp2[i+1] > max_sum)
                max_sum = dp1[i] + dp2[i+1];
            i++;
        }
       return max_sum;
    }
    int maxSumTwoNoOverlap(vector<int>& nums, int firstLen, int secondLen) {
        if(firstLen == secondLen)
            return helper(nums, firstLen, secondLen);
        else
            return max(helper(nums, firstLen, secondLen), helper(nums, secondLen, firstLen));
    }
};