`n` students `[0, ..., n-1]` participate in a marathon. You are given an int array `standings` where `standings[i] = j` means that student `j` finished just before student `i`. `standings[k] = -1` means that `k` is the first student. There are no ties. List out the students in the order in which they finished the marathon.\n\n**Example:**\n```\nInput: [-1, 0, 1]\nOutput: [0, 1, 2]\n```\n\n**Follow-up:**\nThere are ties.\n\n**Example:**\n```\nInput: [-1, 0, 0]\nOutput: [0, 1, 2]\n```

n students [0, ..., n-1] participate in a marathon. You are given an int array standings where standings[i] = j means that student j finished just before studen