백준 11659번

원본 : https://www.acmicpc.net/problem/11659

11659번: 구간 합 구하기 4

 

풀이

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    private static final BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
    private static final StringBuilder stringBuilder = new StringBuilder();

    public static void main(String[] args) throws Exception {
        StringTokenizer stringTokenizer = new StringTokenizer(bufferedReader.readLine());

        int n = Integer.parseInt(stringTokenizer.nextToken());
        int m = Integer.parseInt(stringTokenizer.nextToken());

        int[] arr = new int[n];
        stringTokenizer = new StringTokenizer(bufferedReader.readLine());

        for (int i = 0; i < n; i++) {
            if (i == 0) {
                arr[i] = Integer.parseInt(stringTokenizer.nextToken());
            } else {
                arr[i] = arr[i - 1] + Integer.parseInt(stringTokenizer.nextToken());
            }
        }

        for (int i = 0; i < m; i++) {
            stringTokenizer = new StringTokenizer(bufferedReader.readLine());
            int start = Integer.parseInt(stringTokenizer.nextToken());
            int end = Integer.parseInt(stringTokenizer.nextToken());

            if (start > 1) {
                stringBuilder.append(arr[end - 1] - arr[start - 2]);
            } else {
                stringBuilder.append(arr[end - 1]);
            }

            stringBuilder.append("\n");
        }

        System.out.println(stringBuilder);
    }
}