[PAT] 1046 Shortest Distance （20 分）Java

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 [3,10​5​​]), followed by N integer distances D​1​​ D​2​​ ⋯ D​N​​, where D​i​​ is the distance between the i-th and the (i+1)-st exits, and D​N​​ is 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 (≤10​4​​), 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 10​7​​.

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

package pattest;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 * @Auther: Xingzheng Wang
 * @Date: 2019/2/23 11:17
 * @Description: pattest
 * @Version: 1.0
 */
public class PAT1046 {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String[] first = reader.readLine().split(" ");

        int n = Integer.parseInt(first[0]);
        int[] dis = new int[n + 1];
        int[] arr = new int[n + 1];
        int sum = 0;

        for (int i = 1; i <= n; i++) {
            dis[i] = Integer.parseInt(first[i]);
            sum += dis[i];
            arr[i] = sum;
        }
        int m = Integer.parseInt(reader.readLine());
        for (int i = 0; i < m; i++) {
            String[] line = reader.readLine().split(" ");
            int s = Integer.parseInt(line[0]);
            int e = Integer.parseInt(line[1]);
            if (s > e) {
                int temp = s;
                s = e;
                e = temp;
            }
            int pre1 = arr[e - 1] - arr[s - 1];
            int pre2 = sum - pre1;
            System.out.println(Math.min(pre1,pre2));
        }
    }
}