最短路径笔记（三）：Bellman-Ford

g_s=[1,0,0,3,2]
g_e=[2,1,4,4,3]
g_w=[2,-3,5,2,3]
dis=[0,-1,-1,-1,-1]

for t in range(5):
    if dis[t]==-1:
        dis[t]=float("inf")
v=5
e=5

for k in range(v):
    change=False
    for i in range(e):
        if dis[g_e[i]]>dis[g_s[i]]+g_w[i]:
            dis[g_e[i]]=dis[g_s[i]]+g_w[i]
            change=True
    #优化
    if not change:
        break

print(dis)