joj 2199 the lost number 好题 值得做做

joj 2199 the lost number 好题 值得做做

Status	In/Out	TIME Limit	MEMORY Limit	Submit Times	Solved Users	JUDGE TYPE
	stdin/stdout	3s	40960K	1071	235	Standard

In a interger sequence S there are N(N < 1000000) intergers, there is a initial number I(-2^31 < I <2^31), which is the minimun interger in S, and no two integers are the same. Now can you find the first lost interger L make the sequence is not consecutive. For example, S = { 1, -2, 2, 9, -1 }, then I = -2, and L = 0.

Input

For each case N is in the first line, and next N lines is the sequence S.

Output

Output L for each case in a single line.

Sample Input

5
1
-2
2
9
-1

Sample Output

0

不用走入排序的误区，

可以在线性的时间内完成。

先一趟循环，保存输入的值n[MAX],同时可找出最小的值，

再来一趟循环以此为基准对每个数进行标记，对每个出现的num,mark[num-min]=1;

然后

for(int i=0;;i++)

{if(mark[i]==0)

cout<<i+min;

break;

}
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