U - Grouping https://atcoder.jp/contests/dp/tasks/dp_u

dp_u.py

N = int(input())
a = [list(map(int, input().split())) for _ in range(N)]
dp = [0] * (1 << N)
cst = [0] * (1 << N)
for msk in range(1 << N):       # あらかじめmskグループのときの点数をcstに求めておく
    for i in range(N):
        for j in range(i + 1, N):
            if (msk & (1 << i)) and (msk & (1 << j)):
                cst[msk] += a[i][j]
for msk in range(1 << N):
    msk2 = msk                  # msk2は、mskの部分集合を表す
    while msk2 > 0:
        nxt = dp[msk - msk2] + cst[msk2]
        dp[msk] = max(dp[msk], nxt)
        msk2 = (msk2 - 1) & msk # この式でmskの部分集合を作っていく

print(dp[(1 << N) - 1])