8题。B有傻逼做法但是没出来，不应该。反而最后搞出G出乎意料，lzhnb！
A：
solver：lzh
1 #include <bits/stdc++.h> 2 using namespace std; 3 typedef pair<int, int> pii; 4 typedef long long ll; 5 #define ff first 6 #define ss second 7 #define mp make_pair 8 9 ll dp1[100010], dp2[100010], ans[100010]; 10 int t[100010], sz[100010], sumt[100010], n, T; 11 vector<pii> v[100010]; 12 void dfs0(int x, int pre) { 13 for (auto i : v[x]) 14 if (i.ff != pre) { 15 dfs0(i.ff, x); 16 sz[x] += sz[i.ff]; 17 sumt[x] += sumt[i.ff]; 18 dp1[x] += 1ll * sz[i.ff] * i.ss + dp1[i.ff]; 19 dp2[x] += 1ll * sumt[i.ff] * i.ss + dp2[i.ff]; 20 } 21 sumt[x] += t[x]; 22 sz[x]++; 23 } 24 void dfs(int x, int pre) { 25 ans[x] = 1ll * t[x] * dp1[x] + dp2[x]; 26 for (auto i : v[x]) 27 if (i.ff != pre) { 28 dp1[i.ff] = dp1[x] + 1ll * i.ss * (n - sz[i.ff]) - 1ll * sz[i.ff] * i.ss; 29 dp2[i.ff] = dp2[x] + 1ll * (T - sumt[i.ff]) * i.ss - 1ll * sumt[i.ff] * i.ss; 30 dfs(i.ff, x); 31 } 32 } 33 int main() { 34 scanf("%d", &n); 35 T = 0; 36 for (int i = 1; i <= n; i++) 37 scanf("%d", &t[i]), T += t[i]; 38 for (int i = 1; i <= n - 1; i++) { 39 int x, y, z; 40 scanf("%d%d%d", &x, &y, &z); 41 v[x].push_back(mp(y, z)); 42 v[y].push_back(mp(x, z)); 43 } 44 dfs0(1, -1); 45 dfs(1, -1); 46 for (int i = 1; i <= n; i++) 47 printf("%lld\n", ans[i]); 48 }
B：
有很好的单调栈sb做法，可惜我最后想到了但是没想清楚，崩了。赛后听了bobby的想法才知道我的想法差在哪里。
1 /* basic header */ 2 #include <bits/stdc++.h> 3 /* define */ 4 #define ll long long 5 #define dou double 6 #define pb emplace_back 7 #define mp make_pair 8 #define sot(a,b) sort(a+1,a+1+b) 9 #define rep1(i,a,b) for(int i=a;i<=b;++i) 10 #define rep0(i,a,b) for(int i=a;i<b;++i) 11 #define eps 1e-8 12 #define int_inf 0x3f3f3f3f 13 #define ll_inf 0x7f7f7f7f7f7f7f7f 14 #define lson (curpos<<1) 15 #define rson (curpos<<1|1) 16 /* namespace */ 17 using namespace std; 18 /* header end */ 19 20 const int maxn = 2e5 + 10; 21 int n, k, cnt[maxn], a[maxn], in[maxn], ans[maxn]; 22 23 int main() { 24 for (int i = 0; i < maxn; i++) cnt[i] = in[i] = 0; 25 scanf("%d%d", &n, &k); 26 for (int i = 1; i <= n; i++) { 27 scanf("%d", &a[i]); 28 cnt[a[i]]++; 29 } 30 stack<int>s; 31 s.push(a[1]); cnt[a[1]]--; in[a[1]] = 1; 32 for (int i = 2; i <= n; i++) { 33 cnt[a[i]]--; 34 if (in[a[i]]) continue; 35 for (; !s.empty() && a[i] < s.top() && cnt[s.top()];) { 36 in[s.top()] = 0; 37 s.pop(); 38 } 39 s.push(a[i]); 40 in[a[i]] = 1; 41 } 42 for (int i = k; i >= 1; i--) ans[i] = s.top(), s.pop(); 43 for (int i = 1; i <= k; i++) printf("%d ", ans[i]); 44 puts(""); 45 return 0; 46 }
C：
solver：lzh、czq
1 #include <bits/stdc++.h> 2 using namespace std; 3 typedef pair<int, int> pii; 4 typedef long long ll; 5 #define ff first 6 #define ss second 7 #define mp make_pair 8 9 vector<int>v[100010]; 10 int vis[100010]; 11 int main() { 12 int n, m; scanf("%d%d", &n, &m); 13 for (int i = 1; i <= m; i++) { 14 int x, y; scanf("%d%d", &x, &y); 15 v[x].push_back(y); 16 v[y].push_back(x); 17 } 18 queue<pii>q; 19 q.push(mp(0, 1)); 20 while (!q.empty()) { 21 pii x = q.front(); q.pop(); 22 if (vis[x.ss])continue; 23 vis[x.ss]++; 24 for (auto i : v[x.ss]) 25 if (!vis[i]) { 26 if (i == n) { 27 printf("%d\n", x.ff); return 0; 28 } 29 q.push(mp(x.ff + 1, i)); 30 } 31 } 32 }
D：
solver：lzh、czq
1 #include <bits/stdc++.h> 2 using namespace std; 3 typedef pair<int, int> pii; 4 typedef long long ll; 5 #define ff first 6 #define ss second 7 8 int main() { 9 int a, b, ans = 0; scanf("%d%d", &a, &b); 10 while (a != b) { 11 if (a % 2)a++; 12 else if (a < b) { 13 ans += b - a; 14 break; 15 } else a = a / 2; 16 ans++; 17 } 18 printf("%d\n", ans); 19 }
E：
solver：lzh、zyh
1 #include <bits/stdc++.h> 2 using namespace std; 3 typedef pair<int, int> pii; 4 typedef long long ll; 5 #define ff first 6 #define ss second 7 8 char s[100010]; 9 int a[30]; 10 int main(){ 11 scanf("%s",s+1); 12 int n=strlen(s+1); 13 for(int i=1;i<=n;i++)a[s[i]-'a'+1]++; 14 ll ans=1; 15 ll mod=11092019; 16 for(int i=1;i<=26;i++)ans=ans*(a[i]+1)%mod; 17 printf("%d\n",ans); 18 }
G：
solver：lzh、czq
1 #include <bits/stdc++.h> 2 using namespace std; 3 typedef pair<int, int> pii; 4 typedef long long ll; 5 #define ff first 6 #define ss second 7 8 pii h[200010]; 9 int v1[200010], v2[200010]; 10 int main() { 11 int n; 12 scanf("%d", &n); 13 int cnth = 0, cntv = 0; 14 for (int i = 1; i <= n; i++) { 15 char s[10]; 16 int x, y, z; 17 scanf("%s%d%d%d", s + 1, &x, &y, &z); 18 if (s[1] == 'h') 19 h[++cnth] = make_pair(x - z, x - z + y - 1); 20 else { 21 v1[++cntv] = x - z; 22 v2[cntv] = x - z + y - 1; 23 } 24 } 25 sort(v1 + 1, v1 + 1 + cntv); 26 sort(v2 + 1, v2 + 1 + cntv); 27 ll ans = 0; 28 for (int i = 1; i <= cnth; i++) { 29 int l, r; 30 l = lower_bound(v2 + 1, v2 + 1 + cntv, h[i].ff) - v2; 31 r = upper_bound(v1 + 1, v1 + 1 + cntv, h[i].ss) - v1; 32 ans += r - l; 33 } 34 printf("%lld\n", ans); 35 }
I：
solver：czq
1 /* basic header */ 2 #include <bits/stdc++.h> 3 /* define */ 4 #define ll long long 5 #define dou double 6 #define pb emplace_back 7 #define mp make_pair 8 #define sot(a,b) sort(a+1,a+1+b) 9 #define rep1(i,a,b) for(int i=a;i<=b;++i) 10 #define rep0(i,a,b) for(int i=a;i<b;++i) 11 #define eps 1e-8 12 #define int_inf 0x3f3f3f3f 13 #define ll_inf 0x7f7f7f7f7f7f7f7f 14 #define lson (curpos<<1) 15 #define rson (curpos<<1|1) 16 /* namespace */ 17 using namespace std; 18 /* header end */ 19 20 map<int, int> front, back, dist; 21 22 bool parity(const string &s) { 23 bool ret = false; 24 for (auto i = s.begin(); i != s.end(); ++i) 25 for (auto j = i + 1; j != s.end(); ++j) 26 if (*i > *j) ret = !ret; 27 return ret; 28 } 29 30 string swap(const string &s, int i, int j) { 31 string ret(s); 32 ret[i] = s[j]; ret[j] = s[i]; 33 return ret; 34 } 35 36 bool bfs(const vector<vector<int>> &edges) { 37 queue<int> q; 38 for (auto i : front) { 39 if (i.second == -1) { 40 dist[i.first] = 0; 41 q.push(i.first); 42 } else { 43 dist[i.first] = int_inf; 44 } 45 } 46 dist[-1] = int_inf; 47 while ((int)q.size()) { 48 int u = q.front(); 49 q.pop(); 50 if (dist[u] < dist[-1]) { 51 for (auto v : edges[u]) { 52 auto curr = back.find(v); 53 if (dist[curr->second] == int_inf) { 54 dist[curr->second] = dist[u] + 1; 55 q.push(curr->second); 56 } 57 } 58 } 59 } 60 61 return dist[-1] != int_inf; 62 } 63 64 bool dfs(const vector<vector<int>> &edges, int u, map<int, int> *front, map<int, int> *back, map<int, int> &dist) { 65 if (u == -1) return true; 66 for (auto v : edges[u]) { 67 if (dist.find((*back)[v])->second == dist.find(u)->second + 1) { 68 if (dfs(edges, (*back)[v], front, back, dist)) { 69 (*front)[u] = v; (*back)[v] = u; 70 return true; 71 } 72 } 73 } 74 return false; 75 } 76 77 int main() { 78 int n; cin >> n; 79 vector<string> words(n); 80 unordered_map<string, int> index; 81 vector<vector<int>> edges(n), pwords(2); 82 for (int i = 0; i < n; ++i) { 83 cin >> words[i]; 84 index[words[i]] = i; 85 } 86 int __size = words[0].size(); 87 for (int i = 0; i < n; ++i) { 88 int p = (int)parity(words[i]); 89 pwords[p].push_back(i); 90 if (!p) { 91 for (int a = 0; a < __size; ++a) { 92 for (int b = a + 1; b < __size; ++b) { 93 auto s = swap(words[i], a, b); 94 auto si = index.find(s); 95 if (si != index.end()) 96 edges[i].push_back(si->second); 97 } 98 } 99 } 100 } 101 for (auto i : pwords[0]) front[i] = -1; 102 for (auto i : pwords[1]) back[i] = -1; 103 for (int i = 0; i < n; ++i) dist[i] = int_inf; 104 // flow 105 while (bfs(edges)) 106 for (auto i : front) 107 if (i.second == -1) dfs(edges, i.first, &front, &back, dist); 108 int total_flow = 0; 109 for (auto i : front) total_flow += (i.second != -1); 110 cout << n - total_flow << endl; 111 return 0; 112 }
L：
solver：lzh、zyh
1 #include <bits/stdc++.h> 2 using namespace std; 3 typedef pair<int, int> pii; 4 typedef long long ll; 5 #define ff first 6 #define ss second 7 8 char s[30]; 9 ll ans = 1e18; 10 const ll ansinf = 1e18; 11 int a[30], cal[15][15], len; 12 vector<pii> f[30]; 13 void dfs(int x) { 14 if (ans != ansinf) 15 return; 16 if (x == len - 1) { 17 for (int i = 1; i <= len - 1; i++) { 18 int tmp = 0; 19 for (auto j : f[i]) 20 tmp += cal[a[j.ff]][a[j.ss]]; 21 if (tmp % 10 != s[i] - '0') 22 return; 23 } 24 ans = 0; 25 for (int i = len; i >= 1; i--) 26 ans = ans * 10 + a[i]; 27 return; 28 } 29 for (int i = 0; i <= 9; i++) { 30 int tmp = 0; 31 a[x - len + 1] = i; 32 for (auto j : f[x]) 33 tmp += cal[a[j.ff]][a[j.ss]]; 34 if (tmp % 10 == s[x] - '0') { 35 dfs(x - 1); 36 } 37 } 38 } 39 int main() { 40 for (int i = 0; i <= 9; i++) 41 for (int j = 0; j <= 9; j++) 42 cal[i][j] = i * j % 10; 43 44 scanf("%s", s + 1); 45 int n = strlen(s + 1); 46 if (n % 2 == 0) { 47 printf("-1\n"); 48 return 0; 49 } 50 51 len = (n + 1) / 2; 52 for (int i = 1; i <= len; i++) 53 for (int j = 1; j <= len; j++) 54 f[i + j - 1].push_back(make_pair(i, j)); 55 56 char tmpc[30]; 57 for (int i = 1; i <= n; i++) 58 tmpc[i] = s[n - i + 1]; 59 for (int i = 1; i <= n; i++) 60 s[i] = tmpc[i]; 61 62 dfs(n); 63 if (ans == 1e18) 64 printf("-1\n"); 65 else 66 printf("%lld\n", ans); 67 }
M：
solver：zyh
1 #include <bits/stdc++.h> 2 using namespace std; 3 char Map[2001][2001]; 4 bool vis[2001][2001]; 5 int c[2001][2001]; 6 int cnt = 0; 7 int mx[] = {0, 0, 1, -1}; 8 int my[] = {1, -1, 0, 0}; 9 void dfs(int x, int y) { 10 vis[x][y] = true; 11 c[x][y] = cnt; 12 for (int i = 0; i < 4; ++i) 13 if (!vis[x + mx[i]][y + my[i]] && Map[x + mx[i]][y + my[i]] == '.') { 14 dfs(x + mx[i], y + my[i]); 15 } 16 if (!vis[x - 1][y + 1] && Map[x - 1][y + 1] == '.' && ((Map[x][y + 1] == '.' || Map[x - 1][y] == '.') || (Map[x][y + 1] == '/' && Map[x - 1][y] == '/')) ) dfs(x - 1, y + 1); 17 if (!vis[x - 1][y - 1] && Map[x - 1][y - 1] == '.' && ((Map[x][y - 1] == '.' || Map[x - 1][y] == '.') || (Map[x][y - 1] == '\\' && Map[x - 1][y] == '\\'))) dfs(x - 1, y - 1); 18 if (!vis[x + 1][y - 1] && Map[x + 1][y - 1] == '.' && ((Map[x][y - 1] == '.' || Map[x + 1][y] == '.') || (Map[x][y - 1] == '/' && Map[x + 1][y] == '/'))) dfs(x + 1, y - 1); 19 if (!vis[x + 1][y + 1] && Map[x + 1][y + 1] == '.' && ((Map[x][y + 1] == '.' || Map[x + 1][y] == '.') || (Map[x][y + 1] == '\\' && Map[x + 1][y] == '\\'))) dfs(x + 1, y + 1); 20 } 21 int main() { 22 int n, m; 23 scanf("%d%d", &n, &m); 24 for (int i = 2; i <= n + 1; ++i) { 25 scanf("%s", Map[i] + 2); 26 } 27 for (int i = 0; i <= n + 3; ++i) { 28 Map[i][0] = Map[i][m + 3] = '$'; 29 } 30 for (int i = 0; i <= m + 3; ++i) { 31 Map[0][i] = Map[n + 3][i] = '$'; 32 } 33 for (int i = 1; i <= n + 2; ++i) Map[i][1] = Map[i][m + 2] = '.'; 34 for (int i = 1; i <= m + 2; ++i) Map[1][i] = Map[n + 2][i] = '.'; 35 36 int f1 = 0, f2 = 0; 37 for (int i = 1; i <= n + 2; ++i) 38 for (int j = 1; j <= m + 2; ++j) { 39 if (Map[i][j] == '/' && Map[i][j + 1] == '\\' && Map[i + 1][j] == '\\' && Map[i + 1][j + 1] == '/') ++f1; 40 if (Map[i][j] == '.' && !vis[i][j]) { 41 cnt++; 42 dfs(i, j); 43 f2++; 44 } 45 } 46 printf("%d", f1 + f2 - 1); 47 }