java:

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int k = sc.nextInt();
		int[] a = new int[n];
		for(int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		int sum = 0;
		int p = 0;
//		Arrays.sort(a);(別審錯題了，這裡不需要sort，是從編號最小開始，不是重量最小！！！)
		for(int i = 0; i < n; i++) {
			sum = sum + a[i];
			if(sum >= k) {
				sum = 0;
				p++;
			}
		}
		System.out.println(sum > 0 ? p+1 : p);
	}
}
 

c++:

#include<iostream>
#include<vector>

using namespace std;

int main(){
    int n,k,w;
    vector<int> weight;
    cin>>n>>k;
    for(int i=0; i<n; i++){
        cin>>w;
        weight.push_back(w);
    }
    int temp=0,total;
    for(int j=0; j<n; j++){
        temp += weight[j];
        if(temp>=k){
            temp = 0;
            total++;
        }
    }
    //注意邊界條件：最後一個朋友可以不足重量k
    if(temp!=0)
        total++;
    cout<<total;
    return 0;
}