euler_tour.cpp

#include <cstdio>
#include <vector>
using namespace std;

vector<int> v;
int n,adj[1005][1005];

void f(int x){
    for (int i=1; i<=n; i++) {
        if(adj[x][i]){
            adj[x][i]--;
            adj[i][x]--;
            f(i);
            v.push_back(i); // x->i 로 가는 에지 삽입 (편의상 끝점만)
        }
    }
}

int main(){
    int deg[1005] = {};
    scanf("%d",&n);
    for (int i=1; i<=n; i++) {
        for (int j=1; j<=n; j++) {
            scanf("%d",&adj[i][j]);
            deg[i] += adj[i][j];
        }
        if(deg[i] % 2 == 1){
            puts("-1");
            return 0;
        }
    }
    f(1);
    v.push_back(1);
    for (int i=v.size()-1; i>=0; i--) {
        printf("%d ",v[i]);
    }
}