数据结构习题：删数问题。每一步总是选择一个使剩下的数最小的数字删除，即按高位到低位的顺序搜索，若各位数字递增，则删除最后一个数字；否则删除第一个递减区间的首字符，这样删一位便形成了一个新的数字串。然后回到串首，按上述规则再删除下一个数字-Data Structure Problem: deleted a few problems. Each step is always to　a minimum number to make the rest of the figures deleted, according to the order of highest to lowest, search, if you increment the number, then delete the last digit　otherwise, remove the first interval of the first character of diminishing, so delete a position will form a new string of numbers. Then head back to the train, according to the above rule and then delete the next number