Codeforces 1082 毛毛蟲圖構造&最大權閉合子圖
阿新 • • 發佈：2018-11-29
A
#include<bits/stdc++.h> using namespace std; typedef long long ll; const int MAXN = 55, MAXM = 1000; //int to[MAXM << 1], nxt[MAXM << 1], Head[MAXN], ed = 1; //int cost[MAXM << 1]; //inline void addedge(int u, int v, int c) //{ // to[++ed] = v; // nxt[ed] = Head[u]; // cost[ed] = c;View Code// Head[u] = ed; //} inline void read(ll &v) { v = 0; char c = 0; int p = 1; while (c < '0' || c > '9') { if (c == '-') { p = -1; } c = getchar(); } while (c >= '0' && c <= '9') { v = (v << 3) + (v << 1) + c - '0'; c = getchar(); } v *= p; } int main() { ll T; read(T); while (T--) { ll n, x, y, d; read(n), read(x), read(y), read(d); ll cha = abs(x - y); if (cha % d == 0) { ll ans = cha / d; printf("%I64d\n", ans);continue; } else { ll anser = LLONG_MAX; ll ans1, ans2; ans1 = ans2 = LLONG_MAX; if ((y - 1) % d == 0) { ans1 = (x - 1) / d; if ((x - 1) % d) { ans1++; } ans1 += (y - 1) / d; } if ((n - y) % d == 0) { ans2 = (n - x) / d; if ((n - x) % d) { ans2++; } ans2 += (n - y) / d; } anser = min(anser, min(ans1, ans2)); if (anser == LLONG_MAX) { printf("-1\n"); } else { printf("%I64d\n", anser); } } } }
B
注意一下坑點即可
#include<bits/stdc++.h> using namespace std; typedef long long ll; const int MAXN = 55, MAXM = 1000; //int to[MAXM << 1], nxt[MAXM << 1], Head[MAXN], ed = 1; //int cost[MAXM << 1]; //inline void addedge(int u, int v, int c) //{ // to[++ed] = v; // nxt[ed] = Head[u]; // cost[ed] = c; // Head[u] = ed; //} inline void read(int &v) { v = 0; char c = 0; int p = 1; while (c < '0' || c > '9') { if (c == '-') { p = -1; } c = getchar(); } while (c >= '0' && c <= '9') { v = (v << 3) + (v << 1) + c - '0'; c = getchar(); } v *= p; } vector<pair<int, char> > anss; queue<pair<int, char> > que; int main() { ios_base::sync_with_stdio(0); cin.tie(0); int n; cin >> n; string a; cin >> a; pair<int, char> cnt, zz; cnt.first = cnt.second = 0; int sum = 0; for (int i = 0; i <= n; i++) { if (i == n) { anss.push_back(cnt); break; } if (a[i] != cnt.second) { if (cnt.first != 0) { anss.push_back(cnt); } cnt.first = 1; cnt.second = a[i]; } else { cnt.first++; } } int sz = anss.size(); for (int i = 0; i < sz; i++) { if (anss[i].second == 'G') { sum += anss[i].first; } } int ans = 0; for (int i = 0; i < sz; i++) { cnt = anss[i]; if (cnt.second == 'G') { if (cnt.first == sum) { ans = max(ans, cnt.first); } else { ans = max(ans, cnt.first + 1); } } else { if (cnt.first == 1) { if (i > 0 && i < sz - 1) { ans = max(ans, anss[i - 1].first + anss[i + 1].first); if (anss[i - 1].first + anss[i + 1].first != sum) { ans = max(ans, anss[i - 1].first + anss[i + 1].first + 1); } } } } } cout << ans << endl; }View Code
C
sort一下算下貢獻即可
#include<bits/stdc++.h> using namespace std; typedef long long ll; const int MAXN = 55, MAXM = 1000; //int to[MAXM << 1], nxt[MAXM << 1], Head[MAXN], ed = 1; //int cost[MAXM << 1]; //inline void addedge(int u, int v, int c) //{ // to[++ed] = v; // nxt[ed] = Head[u]; // cost[ed] = c; // Head[u] = ed; //} inline void read(int &v) { v = 0; char c = 0; int p = 1; while (c < '0' || c > '9') { if (c == '-') { p = -1; } c = getchar(); } while (c >= '0' && c <= '9') { v = (v << 3) + (v << 1) + c - '0'; c = getchar(); } v *= p; } int pre[100005]; vector<int> num[100005]; int main() { ios_base::sync_with_stdio(0); cin.tie(0); int n, m; cin >> n >> m; int u, v; for (int i = 1; i <= n; i++) { cin >> u >> v; num[u].push_back(v); } for (int i = 1; i <= m; i++) { if (num[i].size()) { sort(num[i].begin(), num[i].end()); } } int ans = 0; for (int i = 1; i <= m; i++) { int len = num[i].size(); if (len) { int sum = 0; for (int j = 0; j < len; j++) { sum += num[i][len - j - 1]; //cout<<i<<" "<<j<<" "<<sum<<endl; if (sum > 0) { pre[j + 1] += sum; } else { break; } } } } for (int i = 1; i <= 100000; i++) { ans = max(ans, pre[i]); } cout << ans << endl; }View Code
D
構造題 毛毛蟲圖
#include<bits/stdc++.h> using namespace std; const int MAXN = 1000005; inline void read(int &v) { v = 0; char c = 0; int p = 1; while (c < '0' || c > '9') { if (c == '-') { p = -1; } c = getchar(); } while (c >= '0' && c <= '9') { v = (v << 3) + (v << 1) + c - '0'; c = getchar(); } v *= p; } int n, m, a[MAXN], b[MAXN], f[MAXN], s[MAXN], t[MAXN], an, sm, T, z; int main() { int i, j = 1, a1, a2, e = 0; read(n); for (int i = 1; i <= n; i++) { read(a[i]); sm += a[i]; } if (sm < n * 2 - 2) { cout << "NO" << endl; return 0; } for (int i = 1; i <= n; i++) { if (a[i] >= 2) { f[i] = 1; b[++z] = i; if (z >= 2) { s[z] = b[z - 1]; t[z] = i; } } } for (int i = 1; i <= z; i++) { a[b[i]] -= (i != 1) + (i != z); } cout << "YES " << min(z + 1, n - 1) << endl << n - 1 << endl; for (int i = 1; i <= n; i++) { if (a[i] == 1 && !f[i]) { if (!e) { e = 1; a[b[z]]--; s[++z] = i; t[z] = b[z - 1]; } else { for (; !a[b[j]]; j++); a[b[j]]--; s[++z] = i; t[z] = b[j]; } } } for (int i = 2; i <= n; i++) { cout << s[i] << " " << t[i] << endl; } }View Code
G
把每條邊當做一個點 搞最大權閉合子圖即可
//Netflow dumpling #include<bits/stdc++.h> using namespace std; typedef long long ll; const int MAXN = 10050; const int MAXM = 20000; const ll INF = 100000000000000000; ll Head[MAXN], cur[MAXN], lev[MAXN], to[MAXM << 1], nxt[MAXM << 1], ed, S, T; ll f[MAXM << 1]; inline void addedge(int u, int v, ll cap) { to[++ed] = v; nxt[ed] = Head[u]; Head[u] = ed; f[ed] = cap; to[++ed] = u; nxt[ed] = Head[v]; Head[v] = ed; f[ed] = 0; return; } inline bool BFS() { int u; memset(lev, -1, sizeof(lev)); queue<int>q; lev[S] = 0; q.push(S); while (q.size()) { u = q.front(); q.pop(); for (int i = Head[u]; i; i = nxt[i]) if (f[i] && lev[to[i]] == -1) { lev[to[i]] = lev[u] + 1; q.push(to[i]); /* if (to[i] == T) { return 1; } magic one way optimize */ } } memcpy(cur, Head, sizeof Head); return lev[T] != -1; } inline ll DFS(int u, ll maxf) { if (u == T || !maxf) { return maxf; } ll cnt = 0; for (ll &i = cur[u], tem; i; i = nxt[i]) if (f[i] && lev[to[i]] == lev[u] + 1) { tem = DFS(to[i], min(maxf, f[i])); maxf -= tem; f[i] -= tem; f[i ^ 1] += tem; cnt += tem; if (!maxf) { break; } } if (!cnt) { lev[u] = -1; } return cnt; } ll Dinic() { ll ans = 0; while (BFS()) { ans += DFS(S, INF); } return ans; } void init(int SS, int TT) { memset(Head, 0, sizeof(Head)); ed = 1; S = SS; T = TT; return; } int main() { ios_base::sync_with_stdio(0); cin.tie(0); int n, m; ll u, v, c; cin >> n >> m; init(0, n + m + 1); for (int i = 1; i <= n; i++) { cin >> c; addedge(m + i, T, c); } ll summ = 0; for (int i = 1; i <= m; i++) { cin >> u >> v >> c; summ += c; addedge(S, i, c); addedge(i, m + u, INF); addedge(i, m + v, INF); } cout << summ - Dinic() << endl; return 0; }View Code