Create 1673 High_score.cpp

problem is basically based on bellman ford algo can refer this article : 
https://cp-algorithms.com/graph/bellman_ford.html

Author: manitajay

cses graph/1673 High_score.cpp

@@ -0,0 +1,91 @@
+// JAI BAJARANG BALI
+ 
+// manitianajay45
+ 
+// give me some sunshine, give me some rain, give me another chance to grow up once again....
+ 
+// sab moh maya hai....
+ 
+#include <bits/stdc++.h>
+using namespace std;
+ 
+#define ll long long
+#define INF 1e15
+ll n,m;
+ 
+struct ed
+{
+    ll u,v,c;
+};
+ 
+vector<ll> graphf[2505];
+vector<ll> graphr[2505];
+vector<bool> vis1(2505,false);
+vector<bool> visn(2505,false);
+ 
+void dfs(ll v){
+    vis1[v]=true;
+    for(auto u:graphf[v]){
+        if(!vis1[u]){
+            dfs(u);
+        }
+    }
+}
+void dfs1(ll v){
+    visn[v]=true;
+    for(auto u:graphr[v]){
+        if(!visn[u]){
+            dfs1(u);
+        }
+    }
+}
+ 
+int main()
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    cin >> n >> m;
+ 
+    vector<ed> edges;
+    for (ll i = 0; i < m; i++)
+    {
+        ll u, v, c;
+        cin >> u >> v >> c;
+        graphf[u].push_back(v);
+        graphr[v].push_back(u);
+        edges.push_back({u,v,c});
+    }
+    // cout<<"YES"<<endl;
+ 
+    dfs(1);
+    dfs1(n);
+    vector<ll> d(n+1,INT_MIN);
+    d[1]=0;
+    ll ans=-1;
+    bool flag=false;
+    for(ll j=0;j<n;j++){
+        flag=false;
+        for(ll i=0;i<m;i++){
+            ed nd=edges[i];
+            if(d[nd.u]>INT_MIN){
+                if(vis1[nd.v] && visn[nd.v] && d[nd.v]< d[nd.u]+nd.c){
+                    d[nd.v]= d[nd.u]+nd.c;
+                    flag=true;
+                }
+            }
+        }
+        if(j==n-1){
+            ans=d[n];
+        }
+ 
+    }
+    if(flag || d[n]==INT_MIN){
+        cout<<"-1"<<endl;
+        return 0;
+    }
+    cout<<d[n]<<endl;
+ 
+ 
+ 
+    return 0;
+}