diff options
Diffstat (limited to '20.5/feb/plat/minimizing.cpp')
-rw-r--r-- | 20.5/feb/plat/minimizing.cpp | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/20.5/feb/plat/minimizing.cpp b/20.5/feb/plat/minimizing.cpp new file mode 100644 index 0000000..9d5bf95 --- /dev/null +++ b/20.5/feb/plat/minimizing.cpp @@ -0,0 +1,78 @@ +#include <bits/stdc++.h> +#define f first +#define s second +using namespace std; +using ll = long long; +using ii = pair<int, int>; +constexpr int MX = 1e5+5; + +int ans, D[2*MX]; +vector<int> G[MX], H[2*MX]; + +int main() { + if (fopen("in", "r")) freopen("in", "r", stdin), freopen("out", "w", stdout); + cin.tie(0)->sync_with_stdio(0); + + int T; cin >> T; + while (T--) { + int N, M; cin >> N >> M; + for (int u = 1; u <= N; ++u) G[u].clear(); + for (int u = 1; u <= 2*N; ++u) H[u].clear(); + for (int i = 0; i < M; ++i) { + int x, y; cin >> x >> y; + G[x].push_back(y), G[y].push_back(x); + H[x].push_back(y+N), H[y+N].push_back(x); + H[y].push_back(x+N), H[x+N].push_back(y); + } + + for (int u = 1; u <= 2*N; ++u) D[u] = 1e9; + queue<int> q; + D[1] = 0, q.push(1); + while (q.size()) { + int u = q.front(); q.pop(); + for (int v : H[u]) if (D[v] == 1e9) + D[v] = D[u]+1, q.push(v); + } + + if (*max_element(D+1, D+2*N+1) == 1e9) { + cout << N-1 << '\n'; + continue; + } + + /*vector<ii> C; + C.emplace_back(0, 0); + for (int u = 1; u <= N; ++u) { + C.emplace_back(D[u], D[u+N]); + }*/ + + ans = 0; + map<ii, int> f; + map<ii, vector<int>> b; + for (int u = 1; u <= N; ++u) { + ii p(min(D[u], D[u+N]), max(D[u], D[u+N])); + ++f[p], b[p].push_back(u); + } + map<ii, int> ea; + for (auto [p, c] : f) { + int pr = ea[ii(p.f-1, p.s+1)]; + if (p.f+1 == p.s) { + if (p.f == 0) ans += (c+1)/2; + else if (f[ii(p.f-1, p.s-1)]) ans += max((c-pr)+(pr+1)/2, (c+1)/2); + else { + if (pr < c) ans += c-pr; + ans += (c+1)/2; + } + } + else { + ans += c; + if (p.f == 0) ea[p] = c; + else if (f[ii(p.f-1, p.s-1)]) ea[p] += min(c, pr); + else { + if (pr < c) ans += c-pr; + ea[p] = c; + } + } + } + cout << ans << '\n'; + } +} |