結果

問題 No.1301 Strange Graph Shortest Path
ユーザー carrot46
提出日時 2020-11-28 12:40:23
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 286 ms / 3,000 ms
コード長 3,699 bytes
コンパイル時間 1,856 ms
コンパイル使用メモリ 182,088 KB
実行使用メモリ 34,596 KB
最終ジャッジ日時 2024-09-12 22:21:52
合計ジャッジ時間 11,582 ms
ジャッジサーバーID
(参考情報)
judge3 / judge2
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 2
other AC * 33
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ソースコード

diff #
プレゼンテーションモードにする

#include <bits/stdc++.h>
//#include <chrono>
//#pragma GCC optimize("O3")
using namespace std;
#define reps(i,s,n) for(int i = s; i < n; i++)
#define rep(i,n) reps(i,0,n)
#define Rreps(i,n,e) for(int i = n - 1; i >= e; --i)
#define Rrep(i,n) Rreps(i,n,0)
#define ALL(a) a.begin(), a.end()
using ll = long long;
using vec = vector<ll>;
using mat = vector<vec>;
ll N,M,H,W,Q,K,A,B;
string S;
using P = pair<ll, ll>;
const ll INF = (1LL<<60);
template<class T> bool chmin(T &a, const T &b){
if(a > b) {a = b; return true;}
else return false;
}
template<class T> bool chmax(T &a, const T &b){
if(a < b) {a = b; return true;}
else return false;
}
struct edge{
int to, cap, rev;
ll cost;
edge(){}
edge(int a, int b, ll c, int d){
to = a;
cap = b;
cost = c;
rev = d;
}
};
using ve = vector<edge>;
void add_edge(int from, int to, int cap, ll cost, vector<ve> &G, bool directed = true){
rep(_, (directed ? 1 : 2)) {
G[from].emplace_back(to, cap, cost, (int) G[to].size());
G[to].emplace_back(from, 0, -cost, (int) G[from].size() - 1);
swap(to, from);
}
}
bool bellman_ford_for_flow(int s, vector<ve> &G, vec &dist){
//O(|V|^2 + |V||E|)
dist[s] = 0;
int num(0), sz = G.size();
while(num++ < sz){
bool update = false;
rep(v, sz){
if(dist[v] != INF) {
for (edge &e : G[v]) {
if (e.cap > 0 && chmin(dist[e.to], dist[v] + e.cost)) update = true;
}
}
}
if(!update) return true;
}
return false; //failed
}
void dijkstra_for_flow(int s, vector<ve> &G, vec &h, vec &dist, vector<int> &prev_v, vector<int> &prev_e){
typedef struct _comp{
ll cost;
int v;
_comp(){}
_comp(ll a, int b){
cost = a;
v = b;
}
bool operator > (const _comp a){
return cost > a.cost;
}
} mp;
priority_queue<mp, vector<mp>, greater<> > pque;
dist[s] = 0;
pque.emplace(0, s);
while(!pque.empty()){
mp p = pque.top(); pque.pop();
if(dist[p.v] < p.cost) continue;
rep(i, (int)G[p.v].size()){
edge &e = G[p.v][i];
if(e.cap > 0 && chmin(dist[e.to], p.cost + e.cost + h[p.v] - h[e.to])){
prev_v[e.to] = p.v;
prev_e[e.to] = i;
pque.emplace(dist[e.to], e.to);
}
}
}
}
//Validate
ll min_cost_flow(int s, int t, int f, vector<ve> &G, bool minus_exist = true){
//minus_exist : if (edge.cost < 0)
//for graph without negative cycles
int sz = G.size();
ll res(0);
vector<int> prev_v(sz), prev_e(sz);
vec h(sz, minus_exist ? INF : 0);
if(minus_exist && (!bellman_ford_for_flow(s, G, h) || h[t] == INF)) return -1;
while(f > 0){
vec dist(sz, INF);
dijkstra_for_flow(s, G, h, dist, prev_v, prev_e);
if(dist[t] == INF) return -1;
rep(v, sz) h[v] += dist[v];
int d = f;
for(int v = t; v != s; v = prev_v[v]){
chmin(d, G[prev_v[v]][prev_e[v]].cap);
}
f -= d;
res += h[t] * d;
for(int v = t; v != s; v = prev_v[v]){
edge &e = G[prev_v[v]][prev_e[v]];
e.cap -= d;
G[v][e.rev].cap += d;
}
}
return res;
}
int main(){
cin>>N>>M;
vector<ve> G(N);
rep(i, M){
int u, v, c, d;
cin>>u>>v>>c>>d;
--u; --v;
add_edge(u, v, 1, c, G, false);
add_edge(u, v, 1, d, G, false);
}
cout<<min_cost_flow(0, N - 1, 2, G, false)<<endl;
}
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