Buggy python submission (verdict: Runtime Error):
for xy in range(h*w):
    i=xy//w
    j=xy%w
    z=a[i][j]-b[i][j]
    if i==0 and j==0:
        x[0].add(abs(a[0][0]-b[0][0]))
    elif i==0 and j!=0:
        for k in x[j-1]:
            if abs(k+z)<81: x[j].add(abs(k+z))
            elif abs(k-z)<81: x[j].add(abs(k-z))
    elif i%2:
        if j==0:
            for k in x[0]:
                if abs(k+z)<81: y[0].add(abs(k+z))
                if abs(k-z)<81: y[0].add(abs(k-z))
        else:
            for k in x[j]:
                if abs(k+z)<81: y[j].add(abs(k+z))
                if abs(k-z)<81: y[j].add(abs(k-z))
            for k in y[j-1]:
                if abs(k+z)<81: y[j].add(abs(k+z))
                if abs(k-z)<81: y[j].add(abs(k-z))
    else:
        if j==0:
            for k in y[0]:
                if abs(k+z)<81: x[0].add(abs(k+z))
                if abs(k-z)<81: x[0].add(abs(k-z))
        else:
            for k in y[j]:
                if abs(k+z)<81: x[j].add(abs(k+z))
                if abs(k-z)<81: x[j].add(abs(k-z))
            for k in x[j-1]:
                if abs(k+z)<81: x[j].add(abs(k+z))
                if abs(k-z)<81: x[j].add(abs(k-z))
    if j==w-1 and i%2==0:
        y=[set([]) for _ in range(w)]
        ans=min(x[-1])
    elif j==w-1:
        x=[set([]) for _ in range(w)]
        ans=min(y[-1])
print(ans)


Fixed submission:
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
 
H,W = map(int,readline().split())
A = [list(map(int,readline().split())) for _ in range(H)]
B = [list(map(int,readline().split())) for _ in range(H)]
 
X = (H + W) * 80
# X点持った状態から始める
dp = [[0] * W for _ in range(H)]
d = abs(A[0][0] - B[0][0])
dp[0][0] = (1 << (X - d))
for h in range(H):
    for w,(a,b) in enumerate(zip(A[h],B[h])):
        if h == w == 0:
            continue
        d = abs(a - b)
        x = 0
        if h != 0:
            x |= (dp[h-1][w] << d) 
            x |= (dp[h-1][w] >> d)
        if w != 0:
            x |= (dp[h][w-1] << d) 
            x |= (dp[h][w-1] >> d)
        dp[h][w] = x
 
dp = dp[-1][-1]
 
B = bin(dp)[2:]
can_make = [i - X for i,b in enumerate(B[::-1]) if b == '1']
 
answer = min(x if x >= 0 else -x for x in can_make)
print(answer)

Buggy python submission (verdict: Time Limit Exceeded):
h,w=map(int,input().split())
a=[[int(i) for i in input().split()] for i in range(h)]
b=[[int(i) for i in input().split()] for i in range(h)]
for i in range(h):
    if i==0:
        x=[set([]) for _ in range(w)]
    for j in range(w):
        if i==0 and j==0:
            x[0].add(abs(a[0][0]-b[0][0]))
        elif i==0 and j!=0:
            for k in x[j-1]:
                x[j].add(abs(k+(a[i][j]-b[i][j])))
                x[j].add(abs(k+(b[i][j]-a[i][j])))
        elif i%2:
            if j==0:
                for k in x[0]:
                    y[j].add(abs(k+(a[i][j]-b[i][j])))
                    y[j].add(abs(k+(b[i][j]-a[i][j])))
            else:
                for k in x[j]:
                    y[j].add(abs(k+(a[i][j]-b[i][j])))
                    y[j].add(abs(k+(b[i][j]-a[i][j])))
                for k in y[j-1]:
                    y[j].add(abs(k+(a[i][j]-b[i][j])))
                    y[j].add(abs(k+(b[i][j]-a[i][j])))
        else:
            if j==0:
                for k in y[0]:
                    x[j].add(abs(k+(a[i][j]-b[i][j])))
                    x[j].add(abs(k+(b[i][j]-a[i][j])))
            else:
                for k in y[j]:
                    x[j].add(abs(k+(a[i][j]-b[i][j])))
                    x[j].add(abs(k+(b[i][j]-a[i][j])))
                for k in x[j-1]:
                    x[j].add(abs(k+(a[i][j]-b[i][j])))
                    x[j].add(abs(k+(b[i][j]-a[i][j])))

    if i%2==0:
        y=[set([]) for _ in range(w)]
        ans=min(x[-1])
    else:
        x=[set([]) for _ in range(w)]
        ans=min(y[-1])
print(ans)

Fixed submission:
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
 
H,W = map(int,readline().split())
A = [list(map(int,readline().split())) for _ in range(H)]
B = [list(map(int,readline().split())) for _ in range(H)]
 
X = (H + W) * 80
# X点持った状態から始める
dp = [[0] * W for _ in range(H)]
d = abs(A[0][0] - B[0][0])
dp[0][0] = (1 << (X - d))
for h in range(H):
    for w,(a,b) in enumerate(zip(A[h],B[h])):
        if h == w == 0:
            continue
        d = abs(a - b)
        x = 0
        if h != 0:
            x |= (dp[h-1][w] << d) 
            x |= (dp[h-1][w] >> d)
        if w != 0:
            x |= (dp[h][w-1] << d) 
            x |= (dp[h][w-1] >> d)
        dp[h][w] = x
 
dp = dp[-1][-1]
 
B = bin(dp)[2:]
can_make = [i - X for i,b in enumerate(B[::-1]) if b == '1']
 
answer = min(x if x >= 0 else -x for x in can_make)
print(answer)