백준 13305번

원본 : www.acmicpc.net/problem/13305

13305번: 주유소

 

풀이

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.math.BigDecimal;
import java.util.Arrays;

public class Main {

	public static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
	public static BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));

	public static void main(String[] args) throws Exception {
		int n = Integer.parseInt(reader.readLine());
		long length[] = Arrays.stream(reader.readLine().split(" ")).mapToLong(Long::parseLong).toArray();
		long cost[] = Arrays.stream(reader.readLine().split(" ")).mapToLong(Long::parseLong).toArray();
		long result = 0;
		long currentCost = 0;
		
		for (int i = 0; i < n - 1; i++) {
			if (i == 0) {
				currentCost = cost[i];
				result += cost[i] * length[i];
			} else {
				if (cost[i] < currentCost) {
					currentCost = cost[i];
					result += cost[i] * length[i];
				} else {
					result += currentCost * length[i];
				}
			}
		}
		
		BigDecimal bigDecimal = new BigDecimal(result);
		writer.write(bigDecimal.toString());
		writer.flush();
	}
	
}