gistfile1.txt

def find_largest_sum_cycle(n, edges):
    def dfs(node, visited, stack, path_sum, cycle_sums):
        visited[node] = True
        stack[node] = path_sum
        
        next_node = edges[node]
        if next_node != -1:
            if not visited[next_node]:
                dfs(next_node, visited, stack, path_sum + next_node, cycle_sums)
            elif stack[next_node] != -1:
                # Cycle detected
                cycle_sum = path_sum - stack[next_node] + next_node
                cycle_sums.append(cycle_sum)
        
        stack[node] = -1  # Remove the node from the current path

    visited = [False] * n
    stack = [-1] * n  # Keeps track of the nodes in the current path
    cycle_sums = []

    for i in range(n):
        if not visited[i]:
            dfs(i, visited, stack, i, cycle_sums)
    
    return max(cycle_sums) if cycle_sums else -1

# Example usage
n = 23
edges = [4, 4, 14, 13, 8, 8, 0, 8, 14, 9, 15, 11, -1, 10, 15, 22, 22, 22, 22, 22, 21]

print(find_largest_sum_cycle(n, edges))  # Output: 45