| # | 제출 시각 | 아이디 | 문제 | 언어 | 결과 | 실행 시간 | 메모리 |
|---|---|---|---|---|---|---|---|
| 725750 | 2023-04-18T02:03:55 Z | josanneo22 | Alternating Heights (CCO22_day1problem1) | C++17 | 0 ms | 0 KB |
#include<bits/stdc++.h>
using namespace std;
#define int long long
inline int rd(){
int x=0,w=1;
char ch=getchar();
for(;ch>'9'||ch<'0';ch=getchar()) if(ch=='-') w=-1;
for(;ch>='0'&&ch<='9';ch=getchar()) x=x*10+ch-'0';
return x*w;
}
const int maxn = 3e3 + 4;
int n;
vector<int> adj[maxn];
vector<char> color;
vector<int> parent;
int cycle_start, cycle_end;
bool dfs(int v) {
color[v] = 1;
for (int u : adj[v]) {
if (color[u] == 0) {
parent[u] = v;
if (dfs(u))
return true;
}
else if (color[u] == 1) {
cycle_end = v;
cycle_start = u;
return true;
}
}
color[v] = 2;
return false;
}
vector<int> find_cycle() {
color.assign(n, 0);
parent.assign(n, -1);
cycle_start = -1;
for (int v = 0; v < n; v++) {
if (color[v] == 0 && dfs(v))
break;
}
if (cycle_start == -1) {
return { -1 };
}
else {
vector<int> cycle;
cycle.push_back(cycle_start);
for (int v = cycle_end; v != cycle_start; v = parent[v])
cycle.push_back(v);
cycle.push_back(cycle_start);
reverse(cycle.begin(), cycle.end());
return cycle;
}
}
void solve(){
int k,q; cin>>n>>k>>q;
vector<int> a(n);
for(auto&x:a) cin>>x;
if(k==2){
int ok[n+1][n+1];
for(int i=0;i<n;i++){
for(int j=0;j<n;j++){
ok[i][j]=0;
}
}
for(int i=0;i<n;i++){
ok[i][i]=1;
for(int j=i+1;j<n;j++){
if(a[j]!=a[j-1]) ok[i][j]|=ok[i][j-1];
else{
ok[i][j]=0; break;
}
}
}
for(int queries=0;queries<q;queries++){
int l,r; cin>>l>>r;
l--;r--;
if(ok[l][r]) cout<<"YES\n";
else cout<<"NO\n";
}
}
else if(n<=500 && k<=5){
int ok[n+5][n+5];
for(int i=0;i<n;i++) for(int j=0;j<n;j++) ok[i][j]=0;
for(int i=0;i<n;i++){
ok[i][i]=1;
int cnt=0;
for(int j=i+1;j<n;j++){
if(cnt%2==1){
if(i-1>=0)adj[a[i-1]].push_back(a[i]);
if(i+1<=n-1) adj[a[i+1]].push_back(a[i]);
}
else{
if(i+1<=n-1) adj[a[i]].push_back(a[i+1]);
if(i-1>=0) adj[a[i]].push_back(a[i-1]);
}
cnt++;
vector<int> ok=find_cycle();
int yeaaaa=(ok[0]==-1);
if(yeaaaa)ok[i][j]=1;
else{
ok[i][j]=0; break;
}
}
}
for(int queries=0;queries<q;queries++){
int l,r; cin>>l>>r;
l--;r--;
if(ok[l][r]) cout<<"YES\n";
else cout<<"NO\n";
}
}
else {
for(int queries=0;queries<q;queries++){
int l,r; cin>>l>>r;
l--;r--;
for(int i=0;i<n;i++) adj[i].clear();
int cnt=0;
for(int i=l;i<=r;i++){
if(cnt%2==1){
if(i-1>=l)adj[a[i-1]].push_back(a[i]);
if(i+1<=r) adj[a[i+1]].push_back(a[i]);
}
else{
if(i+1<=r) adj[a[i]].push_back(a[i+1]);
if(i-1>=l) adj[a[i]].push_back(a[i-1]);
}
cnt++;
}
vector<int> ok=find_cycle();
int yeaaaa=(ok[0]==-1);
if(yeaaaa) cout<<"YES\n";
else cout<<"NO\n";
}
}
}
signed main()
{
ios_base::sync_with_stdio(0); cin.tie(0);
int tt=1; //cin>>tt;
while(tt--){
solve();
}
}