This documentation is automatically generated by online-judge-tools/verification-helper
#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=0304"
#include "../../template/template.hpp"
#include "../../graph/shortest-path/bellman-ford.hpp"
int main() {
int N, C;
int A[200], O[200], B[200], S[200], D[200];
cin >> N >> C;
vector< int > undefined;
for(int i = 0; i < C; i++) {
string str;
cin >> str;
int tail = 0, a = 0, b = 0, o, s, d = 0;
while(isdigit(str[tail])) a = a * 10 + str[tail++] - '0';
if(str[tail] == '*') o = 2;
else if(str[tail] == '<') o = 0, ++tail;
else o = 1, ++tail;
++tail;
while(isdigit(str[tail])) b = b * 10 + str[tail++] - '0';
if(str[tail] == '+') s = 0;
else s = 1;
++tail;
while(tail < str.size()) d = d * 10 + str[tail++] - '0';
A[i] = --a, B[i] = --b, O[i] = o, S[i] = s, D[i] = d;
if(o == 2) undefined.push_back(i);
}
int ret = -1;
for(int i = 0; i < (1 << undefined.size()); i++) {
for(int j = 0; j < undefined.size(); j++) O[undefined[j]] = (i >> j) & 1;
Edges<> es;
for(int k = 0; k < C; k++) {
if(O[k] == 1) swap(A[k], B[k]);
es.emplace_back(B[k], A[k], 0);
if(S[k] == 0) es.emplace_back(B[k], A[k], -D[k]);
else es.emplace_back(A[k], B[k], D[k]);
if(O[k] == 1) swap(A[k], B[k]);
}
auto dists = bellman_ford(es, N, 0);
if(dists.empty() || *min_element(begin(dists), end(dists)) < 0) continue;
ret = max(ret, *max_element(begin(dists), end(dists)));
}
if(ret >= numeric_limits< int >::max()) cout << "inf" << endl;
else cout << ret << endl;
}
#line 1 "test/verify/aoj-0304.test.cpp"
#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=0304"
#line 1 "template/template.hpp"
#include<bits/stdc++.h>
using namespace std;
using int64 = long long;
const int mod = 1e9 + 7;
const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;
struct IoSetup {
IoSetup() {
cin.tie(nullptr);
ios::sync_with_stdio(false);
cout << fixed << setprecision(10);
cerr << fixed << setprecision(10);
}
} iosetup;
template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 >& p) {
os << p.first << " " << p.second;
return os;
}
template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
is >> p.first >> p.second;
return is;
}
template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
for(int i = 0; i < (int) v.size(); i++) {
os << v[i] << (i + 1 != v.size() ? " " : "");
}
return os;
}
template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
for(T &in : v) is >> in;
return is;
}
template< typename T1, typename T2 >
inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }
template< typename T1, typename T2 >
inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }
template< typename T = int64 >
vector< T > make_v(size_t a) {
return vector< T >(a);
}
template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}
template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
t = v;
}
template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
for(auto &e : t) fill_v(e, v);
}
template< typename F >
struct FixPoint : F {
explicit FixPoint(F &&f) : F(forward< F >(f)) {}
template< typename... Args >
decltype(auto) operator()(Args &&... args) const {
return F::operator()(*this, forward< Args >(args)...);
}
};
template< typename F >
inline decltype(auto) MFP(F &&f) {
return FixPoint< F >{forward< F >(f)};
}
#line 4 "test/verify/aoj-0304.test.cpp"
#line 2 "graph/shortest-path/bellman-ford.hpp"
#line 2 "graph/graph-template.hpp"
/**
* @brief Graph Template(グラフテンプレート)
*/
template< typename T = int >
struct Edge {
int from, to;
T cost;
int idx;
Edge() = default;
Edge(int from, int to, T cost = 1, int idx = -1) : from(from), to(to), cost(cost), idx(idx) {}
operator int() const { return to; }
};
template< typename T = int >
struct Graph {
vector< vector< Edge< T > > > g;
int es;
Graph() = default;
explicit Graph(int n) : g(n), es(0) {}
size_t size() const {
return g.size();
}
void add_directed_edge(int from, int to, T cost = 1) {
g[from].emplace_back(from, to, cost, es++);
}
void add_edge(int from, int to, T cost = 1) {
g[from].emplace_back(from, to, cost, es);
g[to].emplace_back(to, from, cost, es++);
}
void read(int M, int padding = -1, bool weighted = false, bool directed = false) {
for(int i = 0; i < M; i++) {
int a, b;
cin >> a >> b;
a += padding;
b += padding;
T c = T(1);
if(weighted) cin >> c;
if(directed) add_directed_edge(a, b, c);
else add_edge(a, b, c);
}
}
inline vector< Edge< T > > &operator[](const int &k) {
return g[k];
}
inline const vector< Edge< T > > &operator[](const int &k) const {
return g[k];
}
};
template< typename T = int >
using Edges = vector< Edge< T > >;
#line 4 "graph/shortest-path/bellman-ford.hpp"
/**
* @brief Bellman-Ford(単一始点最短路)
* @docs docs/bellman-ford.md
*/
template< typename T >
vector< T > bellman_ford(const Edges< T > &edges, int V, int s) {
const auto INF = numeric_limits< T >::max();
vector< T > dist(V, INF);
dist[s] = 0;
for(int i = 0; i < V - 1; i++) {
for(auto &e : edges) {
if(dist[e.from] == INF) continue;
dist[e.to] = min(dist[e.to], dist[e.from] + e.cost);
}
}
for(auto &e : edges) {
if(dist[e.from] == INF) continue;
if(dist[e.from] + e.cost < dist[e.to]) return vector< T >();
}
return dist;
}
#line 6 "test/verify/aoj-0304.test.cpp"
int main() {
int N, C;
int A[200], O[200], B[200], S[200], D[200];
cin >> N >> C;
vector< int > undefined;
for(int i = 0; i < C; i++) {
string str;
cin >> str;
int tail = 0, a = 0, b = 0, o, s, d = 0;
while(isdigit(str[tail])) a = a * 10 + str[tail++] - '0';
if(str[tail] == '*') o = 2;
else if(str[tail] == '<') o = 0, ++tail;
else o = 1, ++tail;
++tail;
while(isdigit(str[tail])) b = b * 10 + str[tail++] - '0';
if(str[tail] == '+') s = 0;
else s = 1;
++tail;
while(tail < str.size()) d = d * 10 + str[tail++] - '0';
A[i] = --a, B[i] = --b, O[i] = o, S[i] = s, D[i] = d;
if(o == 2) undefined.push_back(i);
}
int ret = -1;
for(int i = 0; i < (1 << undefined.size()); i++) {
for(int j = 0; j < undefined.size(); j++) O[undefined[j]] = (i >> j) & 1;
Edges<> es;
for(int k = 0; k < C; k++) {
if(O[k] == 1) swap(A[k], B[k]);
es.emplace_back(B[k], A[k], 0);
if(S[k] == 0) es.emplace_back(B[k], A[k], -D[k]);
else es.emplace_back(A[k], B[k], D[k]);
if(O[k] == 1) swap(A[k], B[k]);
}
auto dists = bellman_ford(es, N, 0);
if(dists.empty() || *min_element(begin(dists), end(dists)) < 0) continue;
ret = max(ret, *max_element(begin(dists), end(dists)));
}
if(ret >= numeric_limits< int >::max()) cout << "inf" << endl;
else cout << ret << endl;
}