#include <bits/stdc++.h>
#define int long long
#define sz(a) (int)a.size()
#define all(a) a.begin(), a.end()
using namespace std;
struct node {
int sum,index;
node* left, *right;
void update() {
sum = max(left->sum,right->sum);
if(left->sum > right->sum) index=left->index;
else index=right->index;
}
node(){
sum=0;
index=0;
left=NULL;
right=NULL;
}
};
pair<int,int> query(node* root, int left, int right, int qLeft, int qRight) {
if (left > qRight || right < qLeft) return {-1e9,-1};
if (left >= qLeft && right <= qRight) return {root->sum, root->index};
int mid = (left + right) / 2;
pair<int,int> l=query(root->left, left, mid, qLeft, qRight);
pair<int,int> r=query(root->right, mid + 1, right, qLeft, qRight);
if(l.first>r.first) return l;
else return r;
}
void build(node* root, int left, int right, const vector<pair<int,int>>& v) {
if (left == right) {
root->sum = v[left].first;
root->index=v[left].second;
return;
}
int mid = (left + right) / 2;
root->left = new node();
root->right = new node();
build(root->left, left, mid, move(v));
build(root->right, mid+1, right, move(v));
root->update();
}
node* root;
vector<pair<int,int>> a;
vector<int> depth;
vector<int> tree;
vector<vector<int>> child;
int n,m;
void dfs(int x, int d){
depth[x]=d;
for (auto u : child[x]) {
tree[u]=tree[x];
dfs(u,d+1);
}
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(nullptr);
cin >> n >> m;
a.resize(n);
depth.resize(n);
tree.resize(n);
child.resize(n);
unordered_map<int,int> conv;
set<int> cord;
cord.insert(0);
cord.insert(m);
for (int i = 0; i < n; i++){
cin >> a[i].first >> a[i].second;
cord.insert(a[i].first);
cord.insert(a[i].second);
if(a[i].first>a[i].second) {
a[i].second+=m;
cord.insert(a[i].second);
}
}
int x=0;
for (auto u : cord)
{
conv[u]=x;
x++;
}
vector<pair<int,int>> buildSEGTREE(x,{-1e9,-1});
sort(a.begin(),a.end());
for (int i = 0; i < n; i++) {
if(buildSEGTREE[conv[a[i].first]].first<conv[a[i].second]){
buildSEGTREE[conv[a[i].first]]={conv[a[i].second],i};
}
}
root=new node();
build(root, 0,x-1,move(buildSEGTREE));
vector<int> roots;
for (int i = 0; i < n; i++)
{
int p=query(root,0,x-1,conv[a[i].first],conv[a[i].second]).second;
if(p>=0&&p!=i) child[p].push_back(i);
else roots.push_back(i);
}
for (int i = 0; i < sz(roots); i++){
tree[roots[i]]=i;
dfs(roots[i],0);
}
int mn=1e12;
for (int i = 0; i < n; i++){
if(a[i].second>=m){
int p=query(root,0,x-1,conv[0],conv[(a[i].second-m)]).second;
if(p==-1||tree[p]!=tree[i]||i==p) continue;
mn=min(abs(depth[p]-depth[i])+1,mn);
}
}
if(mn==1e12) mn=-1;
cout << mn << "\n";
return 0;
}
/*
10 240
3 68
7 126
40 121
58 152
73 139
89 166
121 197
126 311
212 271
237 350
*/
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
344 KB |
Output is correct |
4 |
Correct |
0 ms |
348 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
1 ms |
344 KB |
Output is correct |
9 |
Incorrect |
1 ms |
348 KB |
Output isn't correct |
10 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
344 KB |
Output is correct |
4 |
Correct |
0 ms |
348 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
1 ms |
344 KB |
Output is correct |
9 |
Incorrect |
1 ms |
348 KB |
Output isn't correct |
10 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
344 KB |
Output is correct |
4 |
Correct |
0 ms |
348 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
1 ms |
344 KB |
Output is correct |
9 |
Incorrect |
1 ms |
348 KB |
Output isn't correct |
10 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
348 KB |
Output is correct |
4 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
348 KB |
Output is correct |
4 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
344 KB |
Output is correct |
4 |
Correct |
0 ms |
348 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
1 ms |
344 KB |
Output is correct |
9 |
Incorrect |
1 ms |
348 KB |
Output isn't correct |
10 |
Halted |
0 ms |
0 KB |
- |