백준 - 2225 - 합분해 (G5)

 1N, K = map(int, input().split())
 2
 3dp = [[0]*(N+1) for _ in range(K+1)]
 4for i in range(1, K+1):
 5    dp[i][0] = 1
 6
 7for i in range(1, K+1):
 8    for j in range(1, N+1):
 9        dp[i][j] = (dp[i-1][j] + dp[i][j-1])%1000000000
10print (dp[K][N])