Submission #831613

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Source Code Expand

import sys
nmlist = list(map(int,input().split(" ")))
N = nmlist[0]
M = nmlist[1]

moves = []
for i in range(M):
    moves.append(list(map(int,input().split(" "))))

box = [[1,0] for i in range(N)]
box[0][1] = 1

for i in range(M):
    before = moves[i][0] - 1
    after = moves[i][1] - 1
    if box[before][0] != 0:
        box[before][0] -= 1
        if box[before][1] == 1:
            box[after][1] = 1
        if box[before][0] == 0:
            box[before][1] = 0
        box[after][0] += 1

output = 0
for i in range(N):
    output += box[i][1]

print(output)

Submission Info

Judge Result