OpenJudge

718:Integer Intervals

总时间限制:
1000ms
内存限制:
65536kB
描述
An integer interval [a,b], a < b, is a set of all consecutive integers beginning with a and ending with b.
Write a program that: finds the minimal number of elements in a set containing at least two different integers from each interval.
输入
The first line of the input contains the number of intervals n, 1 <= n <= 10000. Each of the following n lines contains two integers a, b separated by a single space, 0 <= a < b <= 10000. They are the beginning and the end of an interval.
输出
Output the minimal number of elements in a set containing at least two different integers from each interval.
样例输入
4
3 6
2 4
0 2
4 7
样例输出
4
来源
CEOI 1997
全局题号
718
添加于
2015-11-17
提交次数
192
尝试人数
84
通过人数
73