## 2:Pearl Pairing

- 总时间限制:
- 10000ms
- 单个测试点时间限制:
- 1000ms
- 内存限制:
- 65536kB

- 描述
- At Bessie's recent birthday party, she received N (2 <= N <= 100,000; N%2 == 0) pearls, each painted one of C different colors (1 <= C <= N).

Upon observing that the number of pearls N is always even, her creative juices flowed and she decided to pair the pearls so that each pair of pearls has two different colors.

Knowing that such a set of pairings is always possible for the supplied testcases, help Bessie perform such a pairing. If there are multiple ways of creating a pairing, any solution suffices.
- 输入
- * Line 1: Two space-separated integers: N and C

* Lines 2..C + 1: Line i+1 tells the count of pearls with color i: C_i
- 输出
- * Lines 1..N/2: Line i contains two integers a_i and b_i indicating that Bessie can pair two pearls with respective colors a_i and b_i.
- 样例输入
8 3
2
2
4

- 样例输出
1 3
1 3
2 3
3 2

- 提示
- INPUT DETAILS:

There are 8 pearls and 3 different colors. Two pearls have color I; two have color II; four have color III.

OUTPUT DETAILS:

Bessie pairs each pearl of color III with one of color I and II.
- 来源
- USACO March 2008 Gold

- 全局题号
- 2390
- 提交次数
- 18
- 尝试人数
- 8
- 通过人数
- 4