题解 | 小红的优惠券

import java.util.Scanner;
import java.util.HashMap;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNextLine()) {
            String s = scanner.nextLine();
            int cartAmount = Integer.parseInt(s.split(" ")[0]);
            int num = Integer.parseInt(s.split(" ")[1]);
            HashMap<Integer, Integer> map = new HashMap<>();
            for (int i = 0; i < num; i++) {
                String str = scanner.nextLine();
                map.put(Integer.parseInt(str.split(" ")[0]),
                        Integer.parseInt(str.split(" ")[1]));
            }
            HashMap<Integer, Integer> map1 = new HashMap<>();
            for (Integer integer : map.keySet()) {
                if (integer <= cartAmount) {
                    map1.put(integer, cartAmount - map.get(integer));
                }
            }
            if(map1.keySet().size()==0){
                System.out.println(cartAmount);
                break;
            }
            //100 3
            //300 50
            //200 30
            //50 5
            int minValue = Integer.MAX_VALUE;
            for (Integer value : map1.values()) {
                if (value < minValue) {
                    minValue = value;
                }
            }
            System.out.println(minValue);

        }
    }
}

厉害了我