CCF CSP202112-1 序列查询【100分】

Java版

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int N = sc.nextInt();
        int[] A = new int[n + 1];
        for (int i = 1; i < A.length; i++) {
            int x = sc.nextInt();
            A[i] = x;
        }
        int sum = 0;
        for (int i = 0; i < n; i++) {
            sum += i*(A[i+1]-A[i]);
        }
        sum += n*(N-A[n]);
        System.out.println(sum);
    }
}

C++版

#include
#include
using namespace std;
int main(){
	int n,N;
	scanf("%d %d",&n,&N);
	int last = 0,now,sum = 0;
   	for(int i=0;i<=n;i++){
   		if(i==n) now = N;
		else scanf("%d",&now); //else部分不需要包含大括号{} 
		//i对应f[i]从0--n，f[i]最大为n;
		//(now-last)对应f[i]的个数，数组数据每相邻两个数之间的差 
		sum += i * (now -last);	
		last = now;
	}
	cout<