Hello, I have been trying a lot to solve [Trail Maintence(LOJ)](http://www.lightoj.com/volume_showproblem.php?problem=1123), but I am getting RTE every time. I have been trying in many different ways, but at last I am getting RTE, don't know why. Can anyone help me debugging it please?↵
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**Thanks in advance**↵
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<spoiler summary="MyCcode">↵
/**↵
*here mst means minimum spanning tree↵
↵
↵
~~~~~↵
/**↵
*First of all, I will be taking input until the whole graph is connected, and also,↵
*For every query, I have to output -1.↵
*After getting the whole graph connected, I have to perform my first MST. ↵
*then I will output the mst as well.↵
*then I have to input every remained query and for every steps, the last added edge↵
*will make e cycle, and we have to remove the largest edge form the graph, which is unnecessary.. then.. output themst ofans it :D ↵
**/↵
↵
#include <bits/stdc++.h>↵
using namespace std;↵
↵
const int N = 503;↵
↵
struct pii{↵
int a;↵
int b;↵
int c;↵
pii(){a = 0,b = 0,c = 0;}↵
pii(int m,int n,int o){↵
a = m;↵
b = n;↵
c = o;↵
}↵
};bool operator<(pii a,pii b){return a.c < b.c;}↵
int n,pos,size,ans,parent[N],q,u,v,w;↵
vector<pii>mst;↵
pii ara[N+12];↵
↵
void makeset(){for(int i = 0; i < N;i++)parent[i] = i;}↵
int find(int n){return n==parent[n]?n:parent[n]=find(parent[n]);}↵
void Union(int a,int b){ parent[find(a)] = find(b);}↵
↵
↵
int first_mst()↵
{↵
sort(mst.begin(),mst.end());↵
makeset();↵
size = mst.size();↵
int sum = 0;↵
for(int i = 0; i < size;i++){↵
if(find(mst[i].a) != find(mst[i].b)){↵
Union(mst[i].a,mst[i].b);↵
ara[pos++] = pii(mst[i].a,mst[i].b,mst[i].c);↵
sum += mst[i].c;↵
}↵
} ↵
return sum;↵
}↵
↵
void mst2()↵
{↵
↵
size = pos;↵
sort(ara,ara+size);↵
makeset();↵
int indx = -1;↵
int sum = 0;↵
for(int i = 0; i < size;i++){↵
if(find(ara[i].a) != find(ara[i].b)){↵
Union(ara[i].a,ara[i].b);↵
sum += ara[i].c;↵
}↵
else{↵
indx = i;↵
}↵
}↵
if(indx == pos-1){↵
pos--;↵
}↵
else if(indx != -1){↵
pii mm = ara[pos-1];↵
ara[indx] = mm;↵
pos--;↵
}↵
printf("%d\n",sum);↵
}↵
↵
int main()↵
{↵
//freopen("in.txt","r",stdin);↵
int t,caseno = 0;↵
scanf("%d",&t);↵
while(t--){↵
mst.clear();↵
pos = 0;↵
makeset();↵
scanf("%d%d",&n,&q);↵
printf("Case %d:\n",++caseno);↵
int k = n;↵
while(q--){↵
scanf("%d%d%d",&u,&v,&w);↵
mst.push_back(pii(u,v,w));↵
if(find(u) != find(v)){↵
k--;↵
Union(u,v);↵
}↵
if(k == 1)break;↵
printf("-1\n");↵
}↵
int ans = first_mst();↵
printf("%d\n",ans);↵
while(q--){↵
scanf("%d%d%d",&u,&v,&w);↵
ara[pos++] = pii(u,v,w);↵
mst2();↵
}↵
}↵
return 0;↵
}↵
~~~~~↵
↵
↵
↵
↵
</spoiler>↵
↵
↵
↵
↵
↵
**Thanks in advance**↵
↵
<spoiler summary="My
*here mst means minimum spanning tree
↵
↵
~~~~~↵
/**↵
*First of all, I will be taking input until the whole graph is connected, and also,↵
*For every query, I have to output -1.↵
*After getting the whole graph connected, I have to perform my first MST. ↵
*then I will output the mst as well.↵
*then I have to input every remained query and for every steps, the last added edge↵
*will make e cycle, and we have to remove the largest edge form the graph, which is unnecessary.. then.. output the
**/↵
↵
#include <bits/stdc++.h>↵
using namespace std;↵
↵
const int N = 503;↵
↵
struct pii{↵
int a;↵
int b;↵
int c;↵
pii(){a = 0,b = 0,c = 0;}↵
pii(int m,int n,int o){↵
a = m;↵
b = n;↵
c = o;↵
}↵
};bool operator<(pii a,pii b){return a.c < b.c;}↵
int n,pos,size,ans,parent[N],q,u,v,w;↵
vector<pii>mst;↵
pii ara[N+12];↵
↵
void makeset(){for(int i = 0; i < N;i++)parent[i] = i;}↵
int find(int n){return n==parent[n]?n:parent[n]=find(parent[n]);}↵
void Union(int a,int b){ parent[find(a)] = find(b);}↵
↵
↵
int first_mst()↵
{↵
sort(mst.begin(),mst.end());↵
makeset();↵
size = mst.size();↵
int sum = 0;↵
for(int i = 0; i < size;i++){↵
if(find(mst[i].a) != find(mst[i].b)){↵
Union(mst[i].a,mst[i].b);↵
ara[pos++] = pii(mst[i].a,mst[i].b,mst[i].c);↵
sum += mst[i].c;↵
}↵
} ↵
return sum;↵
}↵
↵
void mst2()↵
{↵
↵
size = pos;↵
sort(ara,ara+size);↵
makeset();↵
int indx = -1;↵
int sum = 0;↵
for(int i = 0; i < size;i++){↵
if(find(ara[i].a) != find(ara[i].b)){↵
Union(ara[i].a,ara[i].b);↵
sum += ara[i].c;↵
}↵
else{↵
indx = i;↵
}↵
}↵
if(indx == pos-1){↵
pos--;↵
}↵
else if(indx != -1){↵
pii mm = ara[pos-1];↵
ara[indx] = mm;↵
pos--;↵
}↵
printf("%d\n",sum);↵
}↵
↵
int main()↵
{↵
//freopen("in.txt","r",stdin);↵
int t,caseno = 0;↵
scanf("%d",&t);↵
while(t--){↵
mst.clear();↵
pos = 0;↵
makeset();↵
scanf("%d%d",&n,&q);↵
printf("Case %d:\n",++caseno);↵
int k = n;↵
while(q--){↵
scanf("%d%d%d",&u,&v,&w);↵
mst.push_back(pii(u,v,w));↵
if(find(u) != find(v)){↵
k--;↵
Union(u,v);↵
}↵
if(k == 1)break;↵
printf("-1\n");↵
}↵
int ans = first_mst();↵
printf("%d\n",ans);↵
while(q--){↵
scanf("%d%d%d",&u,&v,&w);↵
ara[pos++] = pii(u,v,w);↵
mst2();↵
}↵
}↵
return 0;↵
}↵
~~~~~↵
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</spoiler>↵
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