Danov1802 27.3

#include <iostream>
#include <vector>
#include <cmath>

using namespace std;

int main(){
    int n;
    cin>>n;

    vector< vector<int> > ways(n, vector<int>(2, -0x80000000)); //[][0]чет   [][1]нечет
    ways[0][0]=0;

    for(int j=1;j<n;j++){
        int a;
        cin>>a;
        if(ways[j-1][0] != -0x80000000){
            ways[j][abs((ways[j-1][0]+a)%2)]=ways[j-1][0]+a;
        }
        if(ways[j-1][1] != -0x80000000){
            ways[j][abs((ways[j-1][1]+a)%2)]=ways[j-1][1]+a;
        }
    }

    for(int i=1;i<n;i++){
        for(int j=0;j<n;j++){
            int a;
            cin>>a;

            vector<int> buffer (2, -0x80000000);

            if(ways[j][0] != -0x80000000){
                buffer[abs((ways[j][0]+a)%2)]=ways[j][0]+a;
            }

            if(ways[j][1] != -0x80000000){
                buffer[abs((ways[j][1]+a)%2)]=ways[j][1]+a;
            }

            ways[j] = buffer;
        }

        for(int j=1;j<n;j++){
            int a;
            cin>>a;

            if(ways[j-1][0] != -0x80000000){
                ways[j][abs((ways[j-1][0]+a)%2)]=max(ways[j][abs((ways[j-1][0]+a)%2)] , ways[j-1][0]+a);
            }

            if(ways[j-1][1] != -0x80000000){
                ways[j][abs((ways[j-1][1]+a)%2)]=max(ways[j][abs((ways[j-1][1]+a)%2)] , ways[j-1][1]+a);
            }

        }
    }

    if(ways[n-1][0] == -0x80000000){
        cout<<n;
    }
    else{
        cout<<ways[n-1][0];
    }

}