# | Submission time | Handle | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
1041828 | 2024-08-02T08:34:21 Z | stdfloat | Swapping Cities (APIO20_swap) | C++17 | 0 ms | 0 KB |
#include <bits/stdc++.h> #include "swap.h" // #include "grader.cpp" using namespace std; #define int long long using ll = long long; #define ff first #define ss second #define pii pair<int, int> int n; vector<vector<pii>> E; void init(int N, int M, vector<int> U, vector<int> V, vector<int> W) { n = N; E.assign(n, {}); for (int i = 0; i < M; i++) { E[U[i]].push_back({V[i], W[i]}); E[V[i]].push_back({U[i], W[i]}); } } int getMinimumFuelCapacity(int X, int Y) { int l = 0, r = (int)1e9 + 1; while (l < r) { int md = (l + r) >> 1; queue<int> q; vector<bool> visX(n); vector<int> p(n, -1); q.push(X); visX[X] = true; while (!q.empty()) { int x = q.front(); q.pop(); for (auto [i, w] : E[x]) { if (w <= md && !visX[i]) { p[i] = x; q.push(i); visX[i] = true; } } } if (!visX[Y]) { l = md + 1; continue; } bool tr = false; vector<bool> visY(n); queue<pii> q1; q1.push({Y, -1}); visY[Y] = true; while (!q1.empty() && !tr) { auto [x, p] = q1.front(); q1.pop(); for (auto [i, w] : E[x]) { if (w > md || i == p) continue; if (visY[i]) { if (visX[i]) { tr = true; break; } } else { visY[i] = true; q1.push({i, x}); } } } int x = Y; while (x != X && !tr) { x = p[x]; int cnt = 0; for (auto [i, w] : E[x]) { cnt += (w <= md); } tr = (cnt > 2); } if (!tr) l = md + 1; else r = md; } return (l == (int)1e9 + 1 ? -1 : l); }