普及练习场 贪心 纪念品分组

题意理解

代码

import java.util.Arrays;
import java.util.Scanner;

public class Main {

public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int w = scanner.nextInt();
int n = scanner.nextInt();
int[] p = new int
;
for(int i = 0; i < n; i++) {
p[i] = scanner.nextInt();
}
scanner.close();
Arrays.sort(p);
int left = 0;
int right = n - 1;
int missNum = 0;
int groupNum = 0;
while(left < right) {
while(p[left] + p[right] > w) {
right--;
missNum++;
}
if(left != right) {
groupNum++;
left++;
right--;
}
if(left == right) {
missNum++;
}
}
System.out.println(groupNum + missNum);
}
}