| # | Submission time | Handle | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 666075 | 2022-11-27T15:16:59 Z | chanhchuong123 | Crocodile's Underground City (IOI11_crocodile) | C++17 | 0 ms | 0 KB |
#include <bits/stdc++.h>
#include "crocodile.h"
using namespace std;
#define task "C"
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
template <typename T1, typename T2> bool mini(T1 &a, T2 b) {
if (a > b) {a = b; return true;} return false;
}
template <typename T1, typename T2> bool maxi(T1 &a, T2 b) {
if (a < b) {a = b; return true;} return false;
}
const long long INF = 2e18;
const int MAXN = 1e5 + 4;
int n, m, k;
int Exit[MAXN];
bool isExit[MAXN];
vector<pair<int, int>> adj[MAXN];
// subtask1-----------------------------------------------
long long f_sub1[MAXN];
long long dfs_sub1(int u, int p) {
long long &ans = f_sub1[u];
if (ans != INF) return ans;
if (isExit[u]) return ans = 0;
vector<long long> store;
for (pair<int, int> x: adj[u]) if (x.fi != p) {
int v = x.fi, w = x.se; dfs_sub1(v, u);
store.push_back(f_sub1[v] + w);
}
sort(all(store));
return ans = store[1];
}
long long subtask1() {
for (int i = 0; i < n; i++) f_sub1[i] = INF;
return dfs_sub1(0, 0);
}
//--------------------------------------------------------
// subtask23----------------------------------------------
long long d[MAXN][2];
struct node {
long long du;
int u;
bool operator< (const node &other) const {
return du > other.du;
}
};
priority_queue<node> pq;
long long subtask23() {
for (int i = 0; i < n; i++) d[i][0] = d[i][1] = INF;
for (int i = 0; i < k; i++) {
d[Exit[i]][0] = 0;
pq.push({0, Exit[i]});
}
while (pq.size()) {
long long du = pq.top().du;
int u = pq.top().u;
int type = du != 0;
pq.pop();
if (d[u][type] != du) continue;
for (pair<int, int> x: adj[u]) {
int v = x.fi, w = x.se;
if (d[v][0] > du + w) {
if (mini(d[v][1], d[v][0]))
pq.push({d[v][1], v});
d[v][0] = du + w;
pq.push({d[v][0], v});
} else if (d[v][1] > du + w) {
d[v][1] = du + w;
pq.push({d[v][1], v});
}
}
}
return d[0][1];
}
//--------------------------------------------------------
long long travel_plan(int n, int m, int r[][2], int l[], int k, int p[]) {
for (int i = 0; i < m; i++) {
int u = r[i][0], v = r[i][1], w = l[i];
adj[u].push_back(make_pair(v, w));
adj[v].push_back(make_pair(u, w));
}
for (int i = 0; i < k; i++) {
int pos = p[i];
Exit[i] = pos;
isExit[pos] = true;
}
if (m == n - 1) return subtask1();
else return subtask23();
}