模板

递归

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备注

1. 拒绝人肉递归

2. 找最近重复子问题

3. 运用数学归纳法的思维

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def recursion(level, param1, param2, ...):
    # recursion terminator
    if level > MAX_LEVEL:
       process_result
       return

    # process logic in current level
    process(level, data...)

    # drill down
    self.recursion(level + 1, p1, ...)

    # reverse the current level status if needed