洛谷这种错误是什么意思wrong answer too short on line 1.

Question

#include<stdio.h>
#define int long long
signed main(){
int n,m,ans=0;
int a[5005];
scanf("%lld %lld",&n,&m);
for(int i=1;i<=m;i++){
scanf("%lld",&a[i]);
}
a[0]=0,a[m+1]=0;
for(int i=1;i<=m+1;i++){
if(a[i]-a[i-1]>n||a[i]-a[i-1]<-n)n--;
while(i<=m){
if(n==0)ans++;
break;
}
}
if(ans==0)printf("%lld",n);
else printf("Yeah");
}

Answer 1

就是答案错误呗，听取蛙声一片