一直Waiting怎么办？

#include<bits/stdc++.h>
using namespace std;
struct stu{
    int node;
    int a,b,c;
    int m;
}a[301];
bool cmp(stu a,stu b){
    if(a.a+a.b+a.c==b.a+b.b+b.c){
        return a.a>b.a;
    }
    return a.m>b.m;
}
int main(){
    int n;
    cin>>n;
    for(int i=0;i<n;i++){
        cin>>a[i].a>>a[i].b>>a[i].c;
        a[i].node=i;
        a[i].m=a[i].a+a[i].b+a[i].c;
    }
    sort(a[0],a[n-1],cmp);
    for(int i=0;i<n;i++){
        cout<<a[i].node<<" "<<a[i].m<<endl;
    }
}