3-Coloring

#include <bits/stdc++.h>
#define ll long long int
using namespace std;
 
 int V;
void printSolution(int color[]);
bool isSafe(int v,vector<vector<bool>> graph, int color[], int c)
{
    for (int i = 0; i < V; i++)
        if (graph[v][i] && c == color[i])
            return false;
 
    return true;
}
bool graphColoringUtil(vector<vector<bool>> graph, int m, int color[],
                       int v)
{
    if (v == V)
        return true;

    for (int c = 1; c <= m; c++) {
        if (isSafe(v, graph, color, c)) {
            color[v] = c;
            if (graphColoringUtil(graph, m, color, v + 1)
                == true)
                return true;
            color[v] = 0;
        }
    }
    return false;
}
bool graphColoring(vector<vector<bool>> graph, int m)
{
    int color[V];
    for (int i = 0; i < V; i++)
        color[i] = 0;
 
    if (graphColoringUtil(graph, m, color, 0) == false) {
        cout << "Solution does not exist";
        return false;
    }
 
    printSolution(color);
    return true;
}
 
void printSolution(int color[])
{
    for (int i = 0; i < V; i++)
        cout << " " << color[i] << " ";
 
    cout << "\n";
}
int main(){
    int n;
    cin >> n;
    V = n;
    vector<vector<bool>> graph (n, vector<bool>(n,false));
    for(int i = 0; i < n; ++i){
        int e; 
        cin >> e;
        --e;
        graph[i][e]=true;
    }
    graphColoring(graph,3);
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: ACCEPTED

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: ACCEPTED

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: WRONG ANSWER

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: RUNTIME ERROR

Test 13

Verdict: RUNTIME ERROR