求问

为什么我这陀屎山代码能过啊……

#include <bits/stdc++.h>
using namespace std;
int n,m;
int dis[110][110][110][110];
const int mod=1e9;
int main(){
    cin>>n>>m;
    for (int l=1;l<=n;l++){
        for (int r=l;r<=n;r++){
            for (int i=l;i<=r;i++){
                for (int j=l;j<=r;j++){
                    dis[l][r][i][j]=1e9;
                }
                dis[l][r][i][i]=0;
            }
        }
    }
    for (int i=1;i<=m;i++){
        int u,v,w;
        cin>>u>>v>>w;
        for (int l=1;l<=max(u,v);l++){
            for (int r=l;r<=n;r++){
                dis[l][r][u][v]=min(dis[l][r][u][v],w);
                dis[l][r][v][u]=min(dis[l][r][v][u],w);
            }
        }
    }
    for (int l=1;l<=n;l++){
        for (int r=l;r<=n;r++){
            for (int k=l;k<=r;k++){
                for (int i=l;i<=r;i++){
                    for (int j=l;j<=r;j++){
                        dis[l][r][i][j]=min(dis[l][r][i][j],dis[l][r][i][k]+dis[l][r][k][j]);
                    }
                }
            }
        }
    }
    long long ans=0;
    for (int l=1;l<=n;l++){
        for (int r=l;r<=n;r++){
            for (int u=l;u<=r;u++){
                for (int v=u;v<=r;v++){
                    if (dis[l][r][u][v]==1e9){
                        continue;
                    }
                    ans=(ans+dis[l][r][u][v])%mod;
                }
            }
        }    
    }
    cout<<ans;
    return 0;
}

时间复杂度不都$O(n^5)$了吗。
我试过了洛谷也能过所以不是ACGO测评机速度太快的问题。