prim.in

prim算法：可以从任意结点出发,找出与之相连的最小权值的结点,连接,把连接后的结点看成是一个整体,和其他的结点的权值比较,再找出最小权值的结点连接,然后将连接上的结点再看做一个整体,依次类推,直到所

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8 999999999 12 3 10 999999999 999999999
999999999 12 999999999 999999999 6 2 999999999
5 3 999999999 999999999 999999999 7 15
999999999 10 6 999999999 999999999 9 999999999
999999999 999999999 2 7 9 999999999 999999999
999999999 999999999 999999999 15 999999999 999999999