Submission #2860335

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Source Code Expand

#include <iostream>
#include <algorithm>
#include <cmath>
#include <map>
#include <vector>
#include <queue>
#include <functional>
#include <string>
#include <stack>
#include <set>
#include <sstream>
#include <iomanip>
#include <limits>
#include <cstring>

using namespace std;
using ll = long long;
typedef unsigned long long ull;
typedef pair<ll, ll> P;
typedef pair<string, string> sP;
typedef pair<ll, pair<ll, ll>> PP;

const ll MOD = 1e9 + 7;
const ll MOD2 = 998244353;
const ll INF = 1 << 30;
const ll INF2 = 9e18;
const double INF3 = 9e14;
const int dx[4] = { 1,0,-1,0 }, dy[4] = { 0,1,0,-1 };
const int tx[8] = { -1,0,1,-1,1,-1,0,1 }, ty[8] = { -1,-1,-1,0,0,1,1,1 };
#define ALL(x) (x).begin(),(x).end()
#define ALLR(x) (x).rbegin(),(x).rend()
#define pb push_back
#define eb emplace_back
#define fr first
#define sc second

struct edge { ll from, to, cost; };
std::vector<P>v[100010];
edge es[2100];
ll d[1100];
ll n, m, a, b, c;

bool bellman(int s) {
	for (int i = 1;i <= n;i++)d[i] = INF2;
	d[s] = 0;
	for (int j = 0;j < n;j++) {
		for (int i = 0;i < m;i++) {
			edge e = es[i];
			if (d[e.to] > d[e.from] + e.cost) {
				d[e.to] = d[e.from] + e.cost;
				if (j == n - 1 && e.to == n)return true;
			}
		}
	}
	return false;
}

int main() {
	cin >> n >> m;
	for (int i = 0;i < m;i++) {
		cin >> a >> b >> c;
		c *= -1;
		es[i] = edge{ a,b,c };
	}
	if (bellman(1)) cout << "inf" << endl;
	else cout << d[n] * (-1) << endl;
	return 0;
}

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