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Largest sum cycle
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Largest sum cycle
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//{ Driver Code Starts
//Initial Template for C++
#include<bits/stdc++.h>
using namespace std;
// } Driver Code Ends
//User function Template for C++
class Solution
{
public:
long long largestSumCycle(int n, vector<int> edge) {
// code here
vector<int> indegree(n, 0);
for(auto it: edge) {
if(it == -1) continue;
indegree[it]++;
}
queue<int> q;
vector<int> vis(n, false);
for(int i = 0; i < n; i++) {
if(indegree[i] == 0) {
vis[i] = true;
q.push(i);
}
}
while(q.empty() == false) {
int curr = q.front(); q.pop();
int par = edge[curr];
if(par == -1) continue;
if(--indegree[par] == 0) {
q.push(par);
vis[par] = true;
}
}
int res = -1;
for(int i = 0; i < n; i++) {
if(vis[i]) continue;
int val = 0;
for(int st = i; vis[st] == false; st = edge[st]) {
val += st;
vis[st] = true;
}
res = max(res, val);
}
return res;
}
};
//{ Driver Code Starts.
signed main(){
int tc;
cin >> tc;
while(tc--){
int N;
cin >> N;
vector<int> Edge(N);
for(int i=0;i<N;i++){
cin>>Edge[i];
}
Solution obj;
long long ans=obj.largestSumCycle(N, Edge);
cout<<ans<<endl;
}
return 0;
}
// } Driver Code Ends