#include<bits/stdc++.h>
#define pb push_back
#define int long long
#define vi vector<int>
#define vvi vector<vector<int>>
#define pii pair<int, int>
#define vpii vector<pair<int, int>>
#define vc vector<char>
#define vb vector<bool>
#define mii map<int,int>
#define f0r(i,n) for(int i=0;i<n;i++)
#define FOR(i,k,n) for(int i=k;i<n;i++)
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define in(a) int a; cin>>a
#define in2(a,b) int a,b; cin>>a>>b
#define in3(a,b,c) int a,b,c; cin>>a>>b>>c
#define in4(a,b,c,d) int a,b,c,d; cin>>a>>b>>c>>d
#define vin(v,n); vi v(n); f0r(i,n){cin>>v[i];}
#define out(a) cout<<a<<'\n'
#define out2(a,b) cout<<a<<' '<<b<<'\n'
#define out3(a,b,c) cout<<a<<' '<<b<<' '<<c<<'\n'
#define out4(a,b,c,d) cout<<a<<' '<<b<<' '<<c<<' '<<d<<'\n'
#define vout(v) for(auto u : v){cout<<u<<' ';} cout<<'\n'
#define dout(a) cout<<a<<' '<<#a<<'\n'
#define dout2(a,b) cout<<a<<' '<<#a<<' '<<b<<' '<<#b<<'\n'
#define yn(x); if(x){cout<<"YES"<<'\n';}else{cout<<"NO"<<'\n';}
const int leg = 1e9 + 7;
const int mod = 998244353;
using namespace std;
signed main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
//ifstream cin(".in");
//ofstream cout(".out");
in2(n,m);
vpii v;
f0r(i,n){
in2(a,b);
v.pb({a,b});
}
sort(all(v));
vpii w;
int mx = -1;
f0r(i, n){
if(v[i].second + (v[i].first > v[i].second) * m > mx){
w.pb(v[i]);
mx = v[i].second + (v[i].first > v[i].second) * m;
}
}
n = w.size();
/*
f0r(i, n){
out2(w[i].first, w[i].second);
}
*/
bool ok = 1;
f0r(i, n-1){
if(w[i].second < w[i+1].first)ok = 0;
}
if(!ok || n < 2)out(-1);
else{
int ptr = 0;
vi nxt(n);
f0r(i, n){
if(w[i].first < w[i].second){
while(w[i].first <= w[ptr].first && w[ptr].first <= w[i].second){
ptr++;
ptr %= n;
}
}
else{
while(w[ptr].first >= w[i].first || w[ptr].first <= w[i].second){
ptr++;
ptr %= n;
}
}
if(ptr != 0)nxt[i] = ptr - 1;
else nxt[i] = n-1;
}
//vout(nxt);
pii jmp[n][20];
f0r(i, n){
if(w[nxt[i]].first > w[nxt[i]].second){
jmp[i][0] = {nxt[i], 1};
}
else jmp[i][0] = {nxt[i], 0};
}
FOR(i, 1, 20){
f0r(j,n){
jmp[j][i] = {jmp[jmp[j][i-1].first][i-1].first, (jmp[j][i-1].second + jmp[jmp[j][i-1].first][i-1].second)};
}
}
f0r(i, n){
//out2(jmp[i][0].first, jmp[i][0].second);
}
//out("");
f0r(i, n){
//out2(jmp[i][4].first, jmp[i][4].second);
}
int ans = 4e18;
f0r(i, n){
if(jmp[i][0].second == 1 && w[jmp[i][0].first].second >= w[i].first){
ans = min(ans, 2ll);
}
else{
int cur = 0;
int dex = i;
int loops = 0;
for(int j = 19; j>=0; j--){
if(loops == 0){
if(jmp[dex][j].second == 1 && w[jmp[dex][j].first].second < w[i].first){
cur += (1 << j);
loops++;
dex = jmp[dex][j].first;
//out("path 1");
}
else if(jmp[dex][j].second == 0){
cur += (1 << j);
dex = jmp[dex][j].first;
//out("path 2");
}
}
else if(loops == 1){
if(jmp[dex][j].second == 0 && w[jmp[dex][j].first].second < w[i].first){
cur += (1 << j);
dex = jmp[dex][j].first;
//out("path 3");
}
}
//dout2(loops, dex);
}
//out(cur);
ans = min(ans, cur + 2);
}
}
out(ans);
}
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
336 KB |
Output is correct |
2 |
Correct |
1 ms |
336 KB |
Output is correct |
3 |
Incorrect |
1 ms |
504 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
336 KB |
Output is correct |
2 |
Correct |
1 ms |
336 KB |
Output is correct |
3 |
Incorrect |
1 ms |
504 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
336 KB |
Output is correct |
2 |
Correct |
1 ms |
336 KB |
Output is correct |
3 |
Incorrect |
1 ms |
504 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
336 KB |
Output is correct |
2 |
Correct |
1 ms |
336 KB |
Output is correct |
3 |
Correct |
1 ms |
336 KB |
Output is correct |
4 |
Execution timed out |
2050 ms |
336 KB |
Time limit exceeded |
5 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
336 KB |
Output is correct |
2 |
Correct |
1 ms |
336 KB |
Output is correct |
3 |
Incorrect |
1 ms |
336 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
336 KB |
Output is correct |
2 |
Correct |
1 ms |
336 KB |
Output is correct |
3 |
Incorrect |
1 ms |
504 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |