Compilare: main.cpp: In function 'int main()': main.cpp:3:534: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] using namespace std;int read() {int n;scanf("%d", &n);return n;}int main() {freopen("dijkstra.in", "r", stdin);freopen("dijkstra.out", "w", stdout);vector<vector<e>> nodes(read() + 1);for (int m = read(); m; m--) {int a = read();nodes[a].push_back(e(read(), read()));}vector<int> m(nodes.size(), INT_MAX);set<e> c;c.insert(e(0, 1));while (c.size()) {e f = *(c.begin());c.erase(c.begin());if (m[f.second] <= f.first)continue;m[f.second] = f.first;for (e a : nodes[f.second])c.insert(e(a.first + f.first, a.second));}for (int i = 2; i < m.size(); i++)printf("%d ", m[i] == INT_MAX ? 0 : m[i]);return 0;} ~~^~~~~~~~~~ main.cpp: In function 'int read()': main.cpp:3:54: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] using namespace std;int read() {int n;scanf("%d", &n);return n;}int main() {freopen("dijkstra.in", "r", stdin);freopen("dijkstra.out", "w", stdout);vector<vector<e>> nodes(read() + 1);for (int m = read(); m; m--) {int a = read();nodes[a].push_back(e(read(), read()));}vector<int> m(nodes.size(), INT_MAX);set<e> c;c.insert(e(0, 1));while (c.size()) {e f = *(c.begin());c.erase(c.begin());if (m[f.second] <= f.first)continue;m[f.second] = f.first;for (e a : nodes[f.second])c.insert(e(a.first + f.first, a.second));}for (int i = 2; i < m.size(); i++)printf("%d ", m[i] == INT_MAX ? 0 : m[i]);return 0;} ^ main.cpp: In function 'int main()': main.cpp:3:111: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] using namespace std;int read() {int n;scanf("%d", &n);return n;}int main() {freopen("dijkstra.in", "r", stdin);freopen("dijkstra.out", "w", stdout);vector<vector<e>> nodes(read() + 1);for (int m = read(); m; m--) {int a = read();nodes[a].push_back(e(read(), read()));}vector<int> m(nodes.size(), INT_MAX);set<e> c;c.insert(e(0, 1));while (c.size()) {e f = *(c.begin());c.erase(c.begin());if (m[f.second] <= f.first)continue;m[f.second] = f.first;for (e a : nodes[f.second])c.insert(e(a.first + f.first, a.second));}for (int i = 2; i < m.size(); i++)printf("%d ", m[i] == INT_MAX ? 0 : m[i]);return 0;} ^ main.cpp:3:148: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] using namespace std;int read() {int n;scanf("%d", &n);return n;}int main() {freopen("dijkstra.in", "r", stdin);freopen("dijkstra.out", "w", stdout);vector<vector<e>> nodes(read() + 1);for (int m = read(); m; m--) {int a = read();nodes[a].push_back(e(read(), read()));}vector<int> m(nodes.size(), INT_MAX);set<e> c;c.insert(e(0, 1));while (c.size()) {e f = *(c.begin());c.erase(c.begin());if (m[f.second] <= f.first)continue;m[f.second] = f.first;for (e a : nodes[f.second])c.insert(e(a.first + f.first, a.second));}for (int i = 2; i < m.size(); i++)printf("%d ", m[i] == INT_MAX ? 0 : m[i]);return 0;} ^