[BOJ/백준] 17404 RGB 거리 2

N = int(input())
 
INF = float('inf')
 
 
 
arr = [list(map(int,input().split())) for _ in range(N)]
result = float('inf')
for first_room in range(3):
    dp = [[INF]*3 for _ in range(N)]
    dp[0][first_room] = arr[0][first_room]
    for i in range(1,N-1):
        for k in range(3):
            for j in range(3):
                if k !=j:
                    dp[i][k] = min(dp[i-1][j]+arr[i][k],dp[i][k])
 
    for i in range(3):
        for j in range(3):
            if i != j and i != first_room:
                dp[N-1][i] = min(dp[N-2][j]+arr[N-1][i],dp[N-1][i])
    result = min(result,min(dp[N-1]))
 
print(result)

 

 

 

N = int(input())
 
arr = [list(map(int,input().split())) for _ in range(N)]
 
 
INF = float('inf')
result = INF
for first_room_color in range(3):
    dp = [[0]*3 for _ in range(N)]
    for i in range(3):
        if i == first_room_color:
            dp[0][i] = arr[0][i]
        else:
            dp[0][i] = INF
 
    for ind in range(1,N):
        dp[ind][0] = arr[ind][0] + min(dp[ind-1][1],dp[ind-1][2])
        dp[ind][1] = arr[ind][1] + min(dp[ind-1][0],dp[ind-1][2])
        dp[ind][2] = arr[ind][2] + min(dp[ind-1][0],dp[ind-1][1])
 
    for last_room_color in range(3):
        if last_room_color != first_room_color:
            if result > dp[N-1][last_room_color]:
                result = dp[N-1][last_room_color]
 
print(result)