額，只是一道簽到題,emmm直接代碼：

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 using namespace std;
 5 
 6 const int maxn = 1005;
 7 int c[maxn];
 8 int d[maxn];
 9 
10 int main(){
11     int t;
12     scanf("%d", &t);
13     while (t--){
14         int n, m;
 
15         scanf("%d %d", &n, &m);
16         for (int i = 0; i < n; i++){
17             scanf("%d", &c[i]);
18         }
19         for (int i = 0; i < n - 1; i++){
20             scanf("%d", &d[i]);
21         }
22         d[n-1] = 0;
23         int ans = 0;
24         int
 
 i;
25         for (i = 0; i < n; i++){
26             ans = ans + c[i] - m*d[i];
27             if (ans < 0)
28                 break;
29         }
30         if (i == n)
31             printf("Yes\n");
32         else 
33             printf("No\n");
34     }
35     //system("pause");
36
 
     return 0;
37 }

C. Coconut（2017 ACM-ICPC 亞洲區（烏魯木齊賽區）網絡賽）