#include "dreaming.h" #include <bits/stdc++.h> using namespace std; using pii = pair<int, int>; #define ff first #define ss second vector<pii> edge[100005]; int par[100005], X[100005]; bool vis[100005]; pii dfs(int x, int p) { pii ret = {0, x}; for (auto i : edge[x]) { if (i.ss == p) continue; auto t = dfs(i.ss, x); ret = max(ret, pii(t.ff + i.ff, t.ss)); } X[x] = ret.ff; par[x] = p; vis[x] = 1; return ret; } int travelTime(int N, int M, int L, int A[], int B[], int T[]) { for (int i = 0; i < M; ++i) { edge[A[i]].emplace_back(T[i], B[i]); edge[B[i]].emplace_back(T[i], A[i]); } vector<int> vec; int ans, dia = 0; for (int i = 0; i < N; ++i) { if (vis[i]) continue; auto t = dfs(dfs(i, i).ss, -1); int x = t.ss, mn = t.ff; for (; x >= 0; x = par[x]) mn = min(mn, max(X[x], t.ff - X[x])); vec.push_back(mn); dia = max(dia, t.ff); } sort(vec.rbegin(), vec.rend()); if (vec.size() > 2) { ans = L + vec[0] + vec[1]; for (int i = 2; i < vec.size(); ++i) ans = max(ans, L + L + vec[1] + vec[i]); } else if (vec.size() == 2) ans = L + vec[0] + vec[1]; else ans = 0; ans = max(ans, dia); return ans; }

dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:43:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 2; i < vec.size(); ++i) ans = max(ans, L + L + vec[1] + vec[i]);
                   ~~^~~~~~~~~~~~