about running

[YuiQwert]

I meet a strange problem, while running this data:

6
7 42 18 11 45 42
0

here is the code, see the line 56, if I delete this line, I will get RE(in cp editor), if I reserve it, I will get the result AC.

And in VsCode, I can get output though I delete line 56.

I don't know why, could you help me?

// Problem: 木棒
// Contest: AcWing
// URL: https://www.acwing.com/problem/content/169/
// Memory Limit: 64 MB
// Time Limit: 1000 ms
// 
// Powered by CP Editor (https://cpeditor.org)

#include<bits/stdc++.h>
using namespace std;

#define debug(x) cerr << #x << ": " << (x) << endl
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define dwn(i,a,b) for(int i=(a);i>=(b);i--)
#define pb push_back
#define all(x) (x).begin(), (x).end()

using pii = pair<int, int>;
using ll = long long;

inline void read(int &x){
    int s=0; x=1;
    char ch=getchar();
    while(ch<'0' || ch>'9') {if(ch=='-')x=-1;ch=getchar();}
    while(ch>='0' && ch<='9') s=(s<<3)+(s<<1)+ch-'0',ch=getchar();
    x*=s;
}

const int N=55;

int n, w[N];
int sum;
int m;

int g[N];
bool dfs(int u, int cnt, int need){
	if(u==n+1){
		if(cnt<m) return false;
		return true;
	}
	bool ok=0;
	rep(i,1,cnt) if(w[u]+g[i]<=need){
		ok=1;
		g[i]+=w[u];
		if(dfs(u+1, cnt, need)) return true;
		g[i]-=w[u];
	}
	
	if(cnt<m){
		ok=1;
		g[cnt+1]=w[u];
		if(dfs(u+1, cnt+1, need)) return true;
		g[cnt+1]=0;
	}
	
	// cerr<<endl;
	if(!ok) return false;
}

int main(){
	while(cin>>n, n){
		int mx=0;
		sum=0;
		rep(i,1,n) read(w[i]), sum+=w[i], mx=max(mx, w[i]);
		sort(w+1, w+1+n, greater<int>());
		
		int res=1e9;
		for(int i=1; i<=sum/i; i++){
			if(sum%i==0){
				m=sum/i;
				if(m<=n && mx<=i){
					memset(g, 0, sizeof g);
					if(dfs(1, 0, i)){
						res=min(res, i);
					}
				}
				m=i;
				if(m<=n && mx<=sum/i){
					memset(g, 0, sizeof g);
					if(dfs(1, 0, sum/i)){
						res=min(res, sum/i);
					}
				}
			}
		}
		cout<<res<<endl;
	}
	return 0;
}

[ouuan]

There's no return statement after line 57, which results in undefined behavior.

[ouuan]

You should have received a warning either in the compilation message or via the language server.

[YuiQwert]

You should have received a warning either in the compilation message or via the language server.

Thank,

I know this warning, however, I don't know why I can get result after adding the cerr<<endl.

[ouuan]

Undefined behavior is arbitrary.

[YuiQwert]

Yes, maybe is caused by ub. Thk U.