In this HackerEarth Just shortest distance problem solution You are given an empty graph of N vertices and M queries of two types:
  1. Given a number X answer what is the shortest distance from the vertex 1 to the vertex X.
  2. Given two integers X, Y add the new oriented edge from X to Y.

HackerEarth Just shortest distance problem solution


HackerEarth Just shortest distance problem solution.

#include<bits/stdc++.h>

const int N = 1050;

using namespace std;

int n, m;
int dist[N];
vector<int> g[N];

void update(int v)
{
for (int i = 0; i < g[v].size(); i++)
{
int to = g[v][i];
if (dist[to]>dist[v] + 1)
{
dist[to] = dist[v] + 1;
update(to);
}
}
}


int main(){
ios_base::sync_with_stdio(0);

cin >> n >> m;

for (int i = 2; i <= n; i++)
dist[i] = 1e9;

for (int i = 1; i <= m; i++)
{
int tp;
cin >> tp;

if (tp == 1)
{
int x;
cin >> x;
if (dist[x] > 1e8)
cout << -1 << endl;
else
cout << dist[x] << endl;
}
if (tp == 2)
{
int a, b;
cin >> a >> b;
g[a].push_back(b);
if (dist[b] > dist[a] + 1)
{
dist[b] = dist[a] + 1;
update(b);
}
}
}

return 0;
}