FJNU-1152 Fat Brother And Integer

Description

Fat brother recently studied number theory, him came across a very big problem — minimum does not appear positive integer. Fat brother get n positive integers, he needs to find out the least a positive integer and the positive integer is not in his n positive integers.

 

Input

There are multiple test cases. The first line of input contains an integer T (T <= 25) indicating the number of test cases. For each test case:

The first line contains a single integer n (1 <= n <= 1000)

The second line contains n positive integer ai ( 1 <= ai <= 1000000000)

 

Output

For each test case, output the minimum positive integer which didn’t appear in the n positive integer

 

 Sample Input

2

5

1 2 3 4 5

5

1 100 101 102 103

 

Sample Output

6

2

---

即给定数组，输出未出现在该数组中最小的数，注意要先排序，sort的用法。

#include <cstdio>
#include <algorithm>

int main(void)
{
    int t, n;
    int num[1100];

    while(scanf("%d", &t) != EOF)
    {
        while(t--)
        {
            scanf("%d", &n);
            for(int i = 0; i < n; i++)
            {
                scanf("%d", &num[i]);
            }

            std::sort(num, num+n);
            int i = 0;
            if(num[i] > 1)
            {
                printf("1\n");
            }
            else
            {
                for(; i < n-1; i++)
                {
                    if(num[i+1]-num[i] > 1)
                        break;
                }
                printf("%d\n", num[i]+1);
            }
        }
    }
    return 0;

}

 

 

---

STL中自带了排序函数——sort， 通常其表示为 sort(begin, end)，即排序的区间、范围（需包涵<algorithm>和std）。

     

int main(void)
{
　　int a[5] {1, 4, 6, 2, 3};
　　std::sort(a, a+5);
　　return 0;
}

 

 sort默认排序方式为从小到大排列，要想从大到小排列，可以自定义一个函数，做为 sort 的第三个参数。

int main(void)
{
    bool func(int, int);

    std::sort(a, a+5, func);
    
    return 0;
}    


bool func(int a, int b)
{
    return a>b;
}