2098. Subsequence of Size K With the Largest Even Sum
You are given an integer array nums and an integer k. Find the largest even sum of any subsequence of nums that has a length of k.
Return this sum, or -1 if such a sum does not exist.
A subsequence is an array that can be derived from another array by deleting some or no elements without changing the order of the remaining elements.
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| class Solution {
public:
long long largestEvenSum(vector<int>& A, int k) {
sort(begin(A), end(A));
int n = A.size();
long long res = 0;
long long miodd = -1, mieven = -1;
for(int i = n - 1; i >= n - k; i--) {
res += A[i];
if(A[i] & 1) miodd = A[i];
else mieven = A[i];
}
if(res & 1) {
bool reqeven = miodd != -1, reqodd = mieven != -1;
bool findeven = false, findodd = false;
int odd = -1, even = -1;
for(int i = n-k-1; i >= 0; i--) {
if(A[i] & 1 and reqodd and !findodd) {
odd = A[i];
findodd = true;
}
if(A[i] % 2 == 0 and reqeven and !findeven) {
even = A[i];
findeven = true;
}
}
long long rres = -1;
if(reqeven and findeven) {
rres = max(rres, res - miodd + even);
}
if(reqodd and findodd) {
rres = max(rres, res - mieven + odd);
}
return rres;
}
return res;
}
};
|
