INT102-Bellman-Ford Algorithm

INF = 10000


def getGraph() -> tuple:
    G = [
        #a  b  c  d   e
        [0, 4, 5, 0,  0],  # a
        [0, 0, 0, 8,  0],  # b
        [0, 0, 0, 0, -7],  # c
        [0, 0, 0, 0, -6],  # d
        [0, 2, 0, 0,  0]   # e
    ]
    return G, 5


def bellman(G: list, n: int, s: int):
    dis = [INF for _ in range(n)]
    dis[s] = 0 # start from a
    for _ in range(n - 1):
        for i in range(n):
            for j in range(n):
                if G[i][j] != 0 and dis[j] > dis[i] + G[i][j]:
                    dis[j] = dis[i] + G[i][j]
    return dis


if __name__ == '__main__':
    G, n = getGraph()
    dis = bellman(G, n, 0)
    print(dis)