[백준][Java] 21318번 피아노 체조 (누적합)

세 번째 줄에 질문의 개수 Q(1 ≤ Q ≤ 100,000)이 주어진다.

수행시간 반절로 줄이기 System.out.println(..); -> bw.write(sBuilder);

 

 

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
 
 
public class Main {
        
    private static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    private static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
    
    
    public static void main(String[] args) throws IOException{
        int N = stoi(br.readLine());
        
        int[] accum = new int[N+1];
        String[] level = br.readLine().split(" ");
        
        int num = 0;
        for(int i=1; i<=N-1; i++) {
            if(stoi(level[i-1])>stoi(level[i])) {
                num++;
            }
            accum[i] = num;
        }
        accum[N] = num;
        
        StringBuilder sBuilder = new StringBuilder();
        int Q = stoi(br.readLine());
        for(int i=1; i<=Q; i++) {
            String[] str = br.readLine().split(" ");
            int x = stoi(str[0]);
            int y = stoi(str[1]);
            
            if(x==y) {
                sBuilder.append("0\n");
                continue;
            }else {
                sBuilder.append(accum[y-1]-accum[x-1]+"\n");
            }
            
        }
        
        
        
        bw.write(sBuilder.toString());
        bw.flush(); 
        bw.close();
    }
    
    private static int stoi(String input) {
        return Integer.parseInt(input);
    }
    
}