Submission #6838554

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Source Code Expand

#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")

#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)

#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 100001; //check the limits, dummy

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);    
    int N; cin >> N;
    
    int M; cin >> M;
    
    ll P; cin >> P;
    vector<vpl > graph(N);
    vector<vi > graph2(N);
    F0R(i, M) {
		int A, B, C; cin >> A >> B >> C; A--; B--; C-=P;
		graph[A].pb(mp(B, C)); 
		graph2[B].pb(A);
	}
	
	bool foundEnd[N]; F0R(i, N) foundEnd[i] = false;
	queue<int> q;
	q.push(N-1);
	foundEnd[N-1] = true;
	while (!q.empty()) {
		int cur = q.front(); q.pop();
		F0R(i, sz(graph2[cur])) {
			int nxt = graph2[cur][i];
			if (!foundEnd[nxt]) {
				foundEnd[nxt] = true;
				q.push(nxt);
			}
		}
	}
	
	ll dist[N];
	F0R(i, N) {
		dist[i] = -1000000000000;
	}
	dist[0] = 0;
	
	bool found[N]; F0R(i, N) found[i] = false;
	
	found[0] = true;
	
	F0R(i, N) {
		F0R(j, N) {
			if (dist[j] == -1000000000000) continue;
			F0R(k, sz(graph[j])) {
				int nxt = graph[j][k].f;
				found[nxt] = true;
				if (dist[nxt] < dist[j] + graph[j][k].s) {
					dist[nxt] = dist[j]+graph[j][k].s;
				}
			
			}
		}
	}
	
	/*F0R(i, N) {
		cout << dist[i] << " ";
	} cout << endl;*/
	
	F0R(i, N) {
		F0R(j, sz(graph[i])) {
		
			int k = graph[i][j].f;
			if (dist[k] == -1000000000000 || dist[i] == -1000000000000) continue;
			if (dist[k] < dist[i] + graph[i][j].s && foundEnd[k]) {
				cout << -1 << endl; return 0;
			}
		}
	}
	
	cout << max(0LL, dist[N-1]) << endl;
	
    return 0;
}

// read the question correctly (ll vs int)
// template by bqi343

Submission Info

Judge Result