1. #include<iostream>
2. #include<vector>
3. #define NODE 5
4. using namespace std;
5. int graph[NODE][NODE] = {{0, 0, 1, 1, 0},
6.    {1, 0, 1, 0, 0},
7.    {0, 0, 0, 1, 0},
8.    {0, 1, 0, 0, 1},
9.    {1, 0, 0, 0, 0}};
10. void traverse(int u, bool visited[]) {
11.    visited[u] = true; //mark v as visited
12.    for(int v = 0; v<NODE; v++) {
13.       if(graph[u][v]) {
14.          if(!visited[v])
15.             traverse(v, visited);
16.       }
17.    }
18. }
19. bool isConnected() {
20.    bool *vis = new bool[NODE];
21.    //for all vertex u as start point, check whether all nodes are visible or not
22.    for(int u; u < NODE; u++) {
23.       for(int i = 0; i<NODE; i++)
24.          vis[i] = false; //initialize as no node is visited
25.          traverse(u, vis);
26.       for(int i = 0; i<NODE; i++) {
27.          if(!vis[i]) //if there is a node, not visited by traversal, graph is not connected
28.             return false;
29.       }
30.    }
31.    return true;
32. }
33. bool hasEulerPath() {
34.    int an = 0, bn = 0;
35.    if(isConnected() == false){ //when graph is not connected
36.       return false;
37.    }
38.    vector<int> inward(NODE, 0), outward(NODE, 0);
39.    for(int i = 0; i<NODE; i++) {
40.       int sum = 0;
41.       for(int j = 0; j<NODE; j++) {
42.          if(graph[i][j]) {
43.             inward[j]++; //increase inward edge for destination vertex
44.             sum++; //how many outward edge
45.          }
46.       }
47.       outward[i] = sum;
48.    }
49.    //check the condition for Euler paths
50.    if(inward == outward) //when number inward edges and outward edges for each node is same
51.       return true; //Euler Circuit, it has Euler path
52.    for(int i = 0; i<NODE; i++) {
53.       if(inward[i] != outward[i]) {
54.          if((inward[i] + 1 == outward[i])) {
55.             an++;
56.          } else if((inward[i] == outward[i] + 1)) {
57.             bn++;
58.          }
59.       }
60.    }
61.    if(an == 1 && bn == 1) { //if there is only an, and bn, then this has euler path
62.       return true;
63.    }
64.    return false;
65. }
66. int main() {
67.    if(hasEulerPath())
68.       cout << "Euler Path Found.";
69.    else
70.    cout << "There is no Euler Circuit.";
71. }