A
很久很久以前，有 n 个国家，第 i 个国家有 a i 个城市，国家之间一共修建了 m 条双向道路，保证各个国家之间可以相互到达，正在旅行的小龙向你提出了 q 个问题，问你从第一个国家能到达的城市数量第 k 少的国家 有多少个城市，请你帮他找到答案。
#include<iostream>
#include<algorithm>
using namespace std;
int a[1001];
int main()
{
int n,m,q;
cin>>n>>m>>q;
for(int i=0;i<n;i++)
{
cin>>a[i];
}
for(int i=0;i<m;i++)
{
int y,z;
cin>>y>>z;
}
sort(a,a+n);
for(int i=0;i<q;i++)
{
int x;
cin>>x;
cout<<a[x-1]<<endl;
}
}
D
高精度*前缀和维护
using namespace std;
vector<int> mul(vector<int> &A, int b)
{
vector<int> C;
int t = 0;
for (int i = 0; i < A.size() || t; i ++ )
{
if (i < A.size()) t += A[i] * b;
C.push_back(t % 10);
t /= 10;
}
while (C.size() > 1 && C.back() == 0) C.pop_back();
return C;
}
int main()
{
int pp;
cin>>pp;
while(pp--)
{
string a;
string B;
cin >> a >> B;
if(a[0]=='0'||B[0]=='0')
{
cout<<"0\n";
continue;
}
int b=B[0]-'0';
int l=B.size();
int ll=a.size();
vector<int> A;
vector<int>pr(l+ll+1);
for (int i = a.size() - 1; i >= 0; i -- ) A.push_back(a[i] - '0');
auto C = mul(A, b);
reverse(C.begin(),C.end());
for(int i=1;i<=C.size();i++)
{
pr[i]=pr[i-1]+C[i-1];
}
int p=0;
int n=C.size();
int m=B.size();
vector<int>ans;
for(int i=1;i<=n+m-1;i++)
{
int r=min(n+m-1-i+1,n);
int l=max(0,n-i);
int now=p+pr[r]-pr[l];
ans.push_back(now%10);
p=now/10;
}
while(p)
{
ans.push_back(p%10);
p/=10;
}
reverse(ans.begin(),ans.end());
for(auto it:ans)cout<<it;
cout<<endl;
}
return 0;
}
E
字符串哈希
using namespace std;
typedef unsigned long long ull;
const ull P = 131, N = 1e6 + 10;
ull h1[N * 2], h2[N], p[N * 2] = {1};
void geth(string &s, char c, ull *h)
{
for (int i = 1; i < s.size(); i++)
h[i] = h[i - 1] * P + (s[i] == c);
}
ull get(ull *h, int l, int r)
{
return h[r] - h[l - 1] * p[r - l + 1];
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
int n;
cin >> n;
string a, b;
cin >> a >> b;
set<char> st(a.begin(), a.end());
a = ' ' + a + a;
b = ' ' + b;
for (int i = 1; i < N * 2; i++)
p[i] = p[i - 1] * P;
int ans = 0;
for (char c : st)
{
geth(a, c, h1);
geth(b, c, h2);
for (int i = 1; i <= n; i++)
{
if (get(h1, i, i + n - 1) == get(h2, 1, n))
{
ans++;
break;
}
}
}
cout << ans;
return 0;
}
F
签到
using namespace std;
int main()
{
int t;
cin>>t;
while(t--)
{
int f,s;
cin>>f>>s;
cout<<"DHY"<<endl;
}
}
G
BFS*最小生成树
using namespace std;
const int N = 2e5 + 5;
int a[1005][1005], dp[1005][1005];
char map1[1005][1005];
int num = 0, n, m, ts;
int dx[4] = { 0, 0, 1, -1 };
int dy[4] = { 1, -1, 0, 0 };
void bfs(int i, int j) {
queue<pair<int, int>> q;
q.push({ i, j });
vector<vector<int>> dist(1005, vector<int>(1005, 0));
vector<vector<int>> vis(1005, vector<int>(1005, 0));
dist[i][j] = 0;
vis[i][j] = 1;
ts = 1;
while (!q.empty()) {
auto [x, y] = q.front();
q.pop();
if (a[x][y]) {
dp[a[i][j]][a[x][y]] = dist[x][y];
}
for (int k = 0; k < 4; k++) {
int nx = x + dx[k];
int ny = y + dy[k];
if (nx >= 1 && nx <= n && ny >= 1 && ny <= m && map1[nx][ny] != '#' && !vis[nx][ny]) {
vis[nx][ny] = 1;
q.push({ nx, ny });
if (map1[nx][ny] == '*') {
ts++;
}
dist[nx][ny] = dist[x][y] + 1;
}
}
}
}
int prim() {
vector<int> vis(num + 1, 0);
vector<int> dis(num + 1, 0x3f3f3f3f);
dis[1] = 0;
int ans = 0;
for (int i = 1; i <= num; i++) {
int t = -1;
for (int j = 1; j <= num; j++) {
if ((t == -1 || dis[j] < dis[t]) && !vis[j]) {
t = j;
}
}
ans += dis[t];
vis[t] = 1;
for (int j = 1; j <= num; j++) {
if (dis[j] > dp[t][j]) {
dis[j] = dp[t][j];
}
}
}
return ans;
}
void solve() {
cin >> n >> m;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
cin >> map1[i][j];
if (map1[i][j] == '*') {
a[i][j] = ++num;
}
}
}
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if (a[i][j]) {
bfs(i, j);
if (ts < num) {
cout << "No\n";
return;
}
}
}
}
cout << prim() << "\n";
}
signed main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
solve();
return 0;
}
H
模拟
using namespace std;
// 自定义函数 aa 用于判断 b 是否为 a 的后缀
bool aa(const string& a, const string& b) {
int l = a.size() - 1;
int ll = b.size() - 1;
while (l >= 0 && ll >= 0) {
if (a[l] != b[ll]) return false;
l--;
ll--;
}
return true;
}
bool cmp(const string& a, const string& b) {
int i = 0;
while (i < a.size() && i < b.size()) {
if (a[i] != b[i])
return a[i] < b[i];
else
i++;
}
return a.size()< b.size();
}
int main() {
map<string, vector<string>> man;
int n;
cin >> n;
for (int i = 0; i < n; i++) {
string a;
int x;
cin >> a >> x;
for (int j = 0; j < x; j++) {
string b;
cin >> b;
man[a].push_back(b);
}
}
vector<pair<string, vector<string>>> ma(man.begin(), man.end());
// 去重处理
for (auto& entry : ma) {
vector<string>& vec = entry.second;
for (size_t i = 0; i < vec.size(); i++) {
for (size_t j = 0; j < vec.size(); j++) {
if (j == i) continue;
if (aa(vec[i], vec[j])) {
if (vec[i].size() >= vec[j].size()) {
vec.erase(vec.begin() + j);
if (j < i)i--;
j--;
} else {
vec.erase(vec.begin() + i);
i--;
break;
}
}
}
}
}
for (auto& entry : ma) {
sort(entry.second.begin(), entry.second.end(),cmp);
}
cout<<ma.size()<<endl;
for (const auto& entry : ma) {
cout << entry.first << " "<<entry.second.size()<<" ";
for (const auto& str : entry.second) {
cout << str << " ";
}
cout << endl;
}
return 0;
}
J
签到
using namespace std;
char str[100010];
int main()
{
int n;
cin>>n;
int x=0;
int res=0;
for(int i=0;i<n;i++)
{
cin>>str[i];
}
char q[5]={'c','h','u','a','n'};
for(int i=0;i<n;i++)
{
if(str[i]==q[x])
{
x++;
}
else x=0;
if(x==5)
{
x=0;
res++;
}
}
cout<<res;
}
K
假签到
#include<algorithm>
#include<cstring>
#define int long long
using namespace std;
int s[10][10];
void solve() {
int n, m;
cin >> n >> m;
for(int i = 1; i <= n; i++) {
for(int j = 1; j<= m; j++) cin >> s[i][j];
}
int k = max(n, m);
int ans = 9999999;
int x = 0;
if(k > 0) ans = min(ans, s[1][1]);
if(k > 1) {
x = s[1][1] * s[2][2] - s[2][1] * s[1][2];
ans = min(ans, x);
}
if(k > 2) {
x = s[1][1] * s[2][2] * s[3][3] + s[1][2] * s[2][3] * s[3][1] + s[2][1] * s[3][2] * s[1][3] - s[1][3] * s[2][2] * s[3][1] - s[1][2] * s[2][1] * s[3][3] - s[1][1] * s[2][3] * s[3][2];
ans = min(ans, x);
}
if(k > 3) {
x = s[4][1] * s[1][2] * s[2][3] * s[3][4] + s[3][1] * s[4][2] * s[1][3] * s[2][4] + s[2][1] * s[3][2] * s[4][3] * s[1][4] + s[1][1] * s[2][2] * s[3][3] * s[4][4] -
s[1][1] * s[2][4] * s[3][3] * s[4][2] - s[1][2] * s[2][1] * s[3][4] * s[4][3] - s[1][3] * s[2][2] * s[3][1] * s[4][4] - s[1][4] * s[2][3] * s[3][2] * s[4][1];
ans = min(ans, x);
}
if(k > 4) {
x = s[5][1] * s[1][2] * s[2][3] * s[3][4] * s[4][5] + s[4][1] * s[5][2] * s[1][3] * s[2][4] * s[3][5] + s[3][1] * s[4][2] * s[5][3] * s[1][4] * s[2][5] + s[2][1] * s[3][2] * s[4][3] * s[5][4] * s[1][5] + s[1][1] * s[2][2] * s[3][3] * s[4][4] * s[5][5] -
s[1][1] * s[2][5] * s[3][4] * s[4][3] * s[5][2] - s[2][1] * s[1][2] * s[3][5] * s[4][4] * s[5][3] - s[1][3] * s[2][2] * s[3][1] * s[4][5] * s[5][4] - s[1][4] * s[2][3] * s[3][2] * s[4][1] * s[5][5] - s[1][5] * s[2][4] * s[3][3] * s[4][2] * s[5][1];
ans = min(ans, x);
}
cout << ans;
}
signed main()
{
int t = 1;
while(t--) solve();
}
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