题解 | 种树

import sys

def main():
    N = int(sys.stdin.readline().strip())
    array = list(map(int, sys.stdin.readline().strip().split()))
    M = sum(array)

    if max(array) > (M + 1) // 2:
        print('-')
        return

    res = []
    last = -1

    for pos in range(M):
        chosen = False
        rest_after_pick = M - pos - 1

        for i in range(N):
            num = i + 1
            if array[i] == 0 or num == last:
                continue

            # 尝试选择 num
            array[i] -= 1

            # 检查剩余部分是否仍然可行
            if max(array) <= (rest_after_pick + 1) // 2:
                res.append(num)
                last = num
                chosen = True
                break

            # 不可行，撤销
            array[i] += 1

        if not chosen:
            print('-')
            return

    print(' '.join(map(str, res)))

if __name__ == "__main__":
    main()