[Coi2003]A1

题目描述

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输入格式

The first line of the input file contains two whole numbers M and N separated by a space character, 1 ≤ M, N ≤ 100 000, where M is a length of a segment and N is a number of damages occurring on the highway. The second line contains N whole numbers separated by a space character representing the positions of all damages. Each of those numbers is greater than M and less than or equal to 2 000 000 000 (two billion). The sequence of N numbers given in the second line will always be strictly increasing sequence.

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输出格式

The first line of the output file should contain the minimal number of damage fixing teams. The second line should contain all the positions where the first segment can begin. These numbers should be separated by a space character and they must form a strictly increasing sequence.

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样例输入

3 5 
4 5 7 8 9 

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样例输出

2
1

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提示

没有写明提示

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题目来源

没有写明来源