結果

問題 No.1479 Matrix Eraser
ユーザー tokusakurai
提出日時 2021-09-25 10:18:50
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 633 ms / 3,000 ms
コード長 3,196 bytes
コンパイル時間 2,902 ms
コンパイル使用メモリ 209,336 KB
最終ジャッジ日時 2025-01-24 18:04:55
ジャッジサーバーID
(参考情報)
judge2 / judge1
このコードへのチャレンジ
(要ログイン)
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 <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < n; i++)
#define rep2(i, x, n) for (int i = x; i <= n; i++)
#define rep3(i, x, n) for (int i = x; i >= n; i--)
#define each(e, v) for (auto &e : v)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) (int)x.size()
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
const int MOD = 1000000007;
// const int MOD = 998244353;
const int inf = (1 << 30) - 1;
const ll INF = (1LL << 60) - 1;
template <typename T>
bool chmax(T &x, const T &y) {
return (x < y) ? (x = y, true) : false;
};
template <typename T>
bool chmin(T &x, const T &y) {
return (x > y) ? (x = y, true) : false;
};
struct io_setup {
io_setup() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout << fixed << setprecision(15);
}
} io_setup;
struct Bipartite_Matching {
vector<vector<int>> es;
vector<int> d, match;
vector<bool> used, used2;
const int n, m;
Bipartite_Matching(int n, int m) : es(n), d(n), match(m), used(n), used2(n), n(n), m(m) {}
void add_edge(int u, int v) { es[u].push_back(v); }
void _bfs() {
fill(begin(d), end(d), -1);
queue<int> que;
for (int i = 0; i < n; i++) {
if (!used[i]) que.emplace(i), d[i] = 0;
}
while (!que.empty()) {
int i = que.front();
que.pop();
for (auto &e : es[i]) {
int j = match[e];
if (j != -1 && d[j] == -1) { que.emplace(j), d[j] = d[i] + 1; }
}
}
}
bool _dfs(int now) {
used2[now] = true;
for (auto &e : es[now]) {
int u = match[e];
if (u == -1 || (!used2[u] && d[u] == d[now] + 1 && _dfs(u))) {
match[e] = now, used[now] = true;
return true;
}
}
return false;
}
int bipartite_matching() {
fill(begin(match), end(match), -1), fill(begin(used), end(used), false);
int ret = 0;
while (true) {
_bfs();
fill(begin(used2), end(used2), false);
int flow = 0;
for (int i = 0; i < n; i++) {
if (!used[i] && _dfs(i)) flow++;
}
if (flow == 0) break;
ret += flow;
}
return ret;
}
};
int main() {
int H, W;
cin >> H >> W;
int MAX = 500000;
vector<vector<pii>> ps(MAX + 1);
rep(i, H) {
rep(j, W) {
int A;
cin >> A;
ps[A].eb(i, j);
}
}
vector<int> cx(H, 0), cy(W, 0);
int sx = 0, sy = 0;
ll ans = 0;
Bipartite_Matching G(H, W);
rep3(i, MAX, 1) {
if (ps[i].empty()) continue;
if (sz(ps[i]) == 1) {
ans++;
continue;
}
each(e, ps[i]) {
auto [x, y] = e;
G.add_edge(x, y);
}
ans += G.bipartite_matching();
each(e, ps[i]) G.es[e.first].clear();
}
cout << ans << '\n';
}
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