Submission #526845

#	Time	Username	Problem	Language	Result	Execution time	Memory
526845		zhangjishen	Crocodile's Underground City (IOI11_crocodile)	C++98	100 / 100	521 ms	53120 KiB

crocodile

#include<bits/stdc++.h>
using namespace std;

#define mp make_pair
#define pb push_back
#define fi first
#define se second
template<typename T> bool chkmin(T &a, T b){return b < a ? a = b, 1 : 0;}
template<typename T> bool chkmax(T &a, T b){return b > a ? a = b, 1 : 0;}
typedef long long ll;
typedef pair<ll, int> pii;
const int MAXN = 1e5 + 10;
const ll inf = 1e18;

int n, m, k, ext[MAXN];
ll f1[MAXN], f2[MAXN];
vector<pair<int, int> > adj[MAXN];

// update f1[u] and f2[u] with k(path length)
void update(int u, ll d){
	if(d < f1[u])
		f2[u] = f1[u], f1[u] = d;
	else if(d < f2[u])
		f2[u] = d;
}

priority_queue<pii, vector<pii>, greater<pii> > q;
bool fro[MAXN];	// frontier
void dijkstra(){
	for(int i = 1; i <= n; i++)
		f1[i] = f2[i] = inf;
	for(int i = 1; i <= k; i++){
		int u = ext[i];
		f1[u] = f2[u] = 0; q.push(mp(0, u));
	}
	while(!q.empty()){
		pii p = q.top(); q.pop();
		int u = p.se;
		if(fro[u]) continue;	// already inducted on u
		fro[u] = true;	 // DP of u finished
		for(int i = 0; i < (int)adj[u].size(); i++){
			int v = adj[u][i].fi, w = adj[u][i].se;
			if(p.fi + w < f2[v]){
				update(v, p.fi + w);
				q.push(mp(f2[v], v));
			}
		}
	}
}

int travel_plan(int N, int M, int R[][2], int L[], int K, int P[]){
	// input
	n = N, m = M, k = K;
	for(int i = 0; i < m; i++){
		int a = R[i][0] + 1, b = R[i][1] + 1, c = L[i];
		adj[a].pb(mp(b, c));
		adj[b].pb(mp(a, c));
	}
	for(int i = 1; i <= k; i++)
		ext[i] = P[i - 1] + 1;
	// dijkstra
	dijkstra();
	return (int)f2[1];
}

• Subtask 1: 46 / 46
• Subtask 2: 43 / 43
• Subtask 3: 11 / 11