PAT 1046. Shortest Distance

1046. Shortest Distance (20)

The task is really simple: given N exits on a highway which forms a simple cycle, you are supposed to tell the shortest distance between any pair of exits.

Input Specification:

Each input file contains one test case. For each case, the first line contains an integer N (in [3, 105]), followed by N integer distances D1D2... DN, where Diis the distance between the i-th and the (i+1)-st exits, and DNis between the N-th and the 1st exits. All the numbers in a line are separated by a space. The second line gives a positive integer M (<=104), with M lines follow, each contains a pair of exit numbers, provided that the exits are numbered from 1 to N. It is guaranteed that the total round trip distance is no more than 107.

Output Specification:

For each test case, print your results in M lines, each contains the shortest distance between the corresponding given pair of exits.

Sample Input:

5 1 2 4 14 9

3

1 3

2 5

4 1

Sample Output:

3

10

7

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思路：以dis[i]表示1号节点按顺时间方向到达“i号节点顺时钟方向的下一个节点”的距离*(1<

关键点

此题如果没有经过预处理dis数组(把dis数组做成一个累加数组)和sum的做法很容易超时