結果

問題 No.1479 Matrix Eraser
ユーザー se1ka2
提出日時 2021-04-16 20:45:38
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 290 ms / 3,000 ms
コード長 4,794 bytes
コンパイル時間 1,372 ms
コンパイル使用メモリ 100,664 KB
実行使用メモリ 43,520 KB
最終ジャッジ日時 2024-07-02 23:16:52
合計ジャッジ時間 8,531 ms
ジャッジサーバーID
(参考情報)
judge5 / 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 * 39
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#include <iostream>
#include <queue>
#include <map>
using namespace std;
template <typename T>
struct Edge
{
int to;
T cap;
int rev;
int id;
};
template <typename T>
struct Flow
{
int n;
int source;
int sink;
T current_flow;
std::vector<int> d;
std::vector<int> nx;
std::vector<std::vector<Edge<T>>> g;
std::vector<std::pair<int, int>> epos;
Flow(){}
Flow(int n, int source, int sink) : n(n), source(source), sink(sink), current_flow(0){
d.resize(n);
nx.resize(n);
g.resize(n);
}
void add_edge(int from, int to, T cap){
epos.push_back(std::pair<int, int>(from, (int)g[from].size()));
g[from].push_back((Edge<T>){to, cap, (int)g[to].size(), (int)epos.size() - 1});
g[to].push_back((Edge<T>){from, 0, (int)g[from].size() - 1, -1});
}
T delete_edge(int id){
Edge<T> &e = g[epos[id].first][epos[id].second];
Edge<T> &re = g[e.to][e.rev];
int u = re.to, v = e.to;
T delete_f = re.cap;
e.cap = 0;
re.cap = 0;
T reverse_f = delete_f - add_flow(u, v, delete_f);
add_flow(u, source, reverse_f);
add_flow(sink, v, reverse_f);
current_flow -= reverse_f;
return current_flow;
}
void bfs(int s){
fill(d.begin(), d.end(), -1);
std::queue<int> que;
d[s] = 0;
que.push(s);
while(que.size()){
int u = que.front();
que.pop();
for(Edge<T> &e : g[u]){
int v = e.to;
Edge<T> &re = g[v][e.rev];
if(re.cap > 0 && d[v] == -1){
d[v] = d[u] + 1;
que.push(v);
}
}
}
}
T dfs(int u, int s, T f){
if(u == s) return f;
for(int &i = nx[u]; i < (int)g[u].size(); i++){
Edge<T> &e = g[u][i];
int v = e.to;
if(d[v] >= d[u] || e.cap == 0) continue;
if(f == -1) f = e.cap;
else f = std::min(f, e.cap);
T fl = dfs(v, s, f);
if(fl > 0){
e.cap -= fl;
g[e.to][e.rev].cap += fl;
return fl;
}
}
return 0;
}
T add_flow(int r, int s, T max_f){
T res = 0;
while(true){
if(max_f == 0) return res;
bfs(s);
if(d[r] == -1) return res;
for(int i = 0; i < n; i++) nx[i] = 0;
for(T f; (f = dfs(r, s, max_f)) > 0;){
res += f;
if(max_f != -1) max_f -= f;
}
}
}
T max_flow(T max_f = -1){
if(max_f != -1){
max_f -= current_flow;
if(max_f < 0){
current_flow -= add_flow(sink, source, -max_f);
return current_flow;
}
}
current_flow += add_flow(source, sink, max_f);
return current_flow;
}
int get_flow(int id){
Edge<T> &e = g[epos[id].first][epos[id].second];
Edge<T> &re = g[e.to][e.rev];
return re.cap;
}
};
struct BipartiteMatching
{
int p;
int q;
Flow<int> g;
BipartiteMatching(){}
BipartiteMatching(int p, int q) : p(p), q(q){
g.n = p + q + 2;
g.source = p + q;
g.sink = p + q + 1;
g.current_flow = 0;
g.d.resize(g.n);
g.nx.resize(g.n);
g.g.resize(g.n);
for(int i = 0; i < p; i++) g.add_edge(p + q, i, 1);
for(int i = p; i < p + q; i++) g.add_edge(i, p + q + 1, 1);
}
void add_edge(int u, int v){
g.add_edge(u, v + p, 1);
}
int delete_edge(int id){
return g.delete_edge(id + p + q);
}
int max_matching(){
return g.max_flow();
}
bool is_used(int id){
return g.get_flow(id + p + q);
}
};
vector<int> x[500005], y[500005];
int main()
{
int h, w;
cin >> h >> w;
int a[502][502];
for(int i = 0; i < h; i++){
for(int j = 0; j < w; j++){
cin >> a[i][j];
x[a[i][j]].push_back(i);
y[a[i][j]].push_back(j);
}
}
int ans = 0;
for(int k = 500000; k > 0; k--){
int m = x[k].size();
if(m <= 1){
ans += m;
continue;
}
map<int, int> mpx, mpy;
int nx = 0, ny = 0;
for(int i = 0; i < m; i++){
if(!mpx.count(x[k][i])) mpx[x[k][i]] = nx++;
if(!mpy.count(y[k][i])) mpy[y[k][i]] = ny++;
}
BipartiteMatching g(nx, ny);
for(int i = 0; i < m; i++) g.add_edge(mpx[x[k][i]], mpy[y[k][i]]);
ans += g.max_matching();
}
cout << ans << endl;
}
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