I am getting TLE, can someone go through it once, thanks in advance I am getting TLE, can someone go through my code once, thanks in advance

//Link: https://uva.onlinejudge.org/index.php?option=onlinejudge&page=show_problem&problem=2768
 
#include<bits/stdc++.h>
using namespace std;
 
class Graph
{
	public: map<int, list<pair<int, int> > > G;
			map<int, list<pair<int, int> > > Grev;
			int V;
 
	Graph(int v)
	{
		V = v;
	}
 
	void addEdge(int u, int v, int weight)
	{
		G[u].push_back(make_pair(v,weight));

Can anyone help me find the bug, I am getting seg. fault but sample test case is giving correct answer!

//Link: http://www.spoj.com/problems/PPATH/
 
#include<iostream>
#include<vector>
#include<cmath>
#include<queue>
 
using namespace std;
 
bool isPrime(int n)
{
	for(int i=2; i<=sqrt(n); i++)
		if(n%i==0)
			return false;
 
	return true;
}
 
bool check(int a, int b)
{

I couldn't understand the other approaches but I used stack to get the job done, here is how:

"Link: https://www.codechef.com/ZCOPRAC/problems/ZCO12001"
#The idea is that depth is equal to the maximum no of elements
#present on the stack at some instance and
#keep track of index right bracket(when popping occur) for some left bracket
#max no of elments will be present in the largest of range and all ranges are
#stores in start_end array
 
N = int(input()) #INPUT
arr = [0]+list(map(int, input().split())) #INPUT ARRAY     
stack = [] #STACK
start_end = [] #Store (i,j), i->starting index of left bracket
               #j->corresponding right bracket to the left one
 
j = 1
Max = 0
stacklen = 0
while j < len(arr):# Iterate over all values in the array
 
    if arr[j] == 1: #If left bracket then push
        stack.append(j)