Submission #781895

#	Time	Username	Problem	Language	Result	Execution time	Memory
781895		YassineBenYounes	Passport (JOI23_passport)	C++17	6 / 100	54 ms	24684 KiB

passport

#include<bits/stdc++.h>
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef double db;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define pbds tree<pair<ll, ll>, null_type, less<pair<ll,ll>>,rb_tree_tag, tree_order_statistics_node_update>
using namespace __gnu_pbds;
ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;} // greatest common divisor (PGCD)
ll lcm(ll a , ll b) {return (a * b) / gcd(a , b);} // least common multiple (PPCM)
int dx[8] = {1, 0, 0, -1, 1, 1, -1, -1};
int dy[8] = {0, 1, -1, 0, 1, -1, -1, 1};
#define endl "\n"
#define ss second
#define ff first
#define all(x) (x).begin() , (x).end()
#define pb push_back
#define vi vector<int>
#define vii vector<pair<int,int>>
#define vl vector<ll>
#define vll vector<pair<ll,ll>>
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pdd  pair<double,double>
#define vdd  vector<pdd>
#define speed ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
////////////////////Only Clear Code//////////////////////////

void usaco_problem(){
    freopen("milkvisits.in", "r", stdin);
    freopen("milkvisits.out", "w", stdout);
}

void init(){
    #ifndef ONLINE_JUDGE
 
freopen("input.txt", "r", stdin);
 
freopen("output.txt", "w", stdout);
 
#endif // ONLINE_JUDGE
}

const int mx = 2e5+5;
const int LOG = 25;
const ll inf = 1e18;
const ll mod = 1e8;
int n;

int st[mx][LOG], st1[mx][LOG];

int lg[mx];

int r[mx], l[mx];

void pre_log(int n){
    lg[1] = 0;
    for(int i = 2; i <= n;i++){
        lg[i] = lg[i/2]+1;
    }
}

void build(){
    for(int i = 0; i < n;i++){
        st[i][0] = r[i];
    }
    for(int j = 1;j < LOG;j++){
        for(int i = 0; i < n;i++){
            int pos = i + (1 << (j-1));
            if(pos >= n)continue;
            st[i][j] = max(st[i][j-1], st[pos][j-1]);
        }
    }
}

int max_query(int a, int b){
    int sz = b-a+1;
    int k = lg[sz];
    return max(st[a][k], st[b-(1<<k)+1][k]);
}

void run_case(){
    pre_log(mx-1);
    cin >> n;
    for(int i = 0; i < n;i++){
        cin >> l[i] >> r[i];
        l[i]--;r[i]--;
    }
    build();
    int q;cin >> q;
    int a;cin >> a;
    int x = 0, y = r[0];
    int ans = 1;
    while(y != n-1){
        int nxt = max_query(x, y);
        //cout << x << " " << y << " " << nxt << endl;
        if(nxt != y) y = nxt, ans++;
        else{
            cout << -1 << endl;
            return;
        }
    }
    cout << ans << endl;
}

int main(){
    speed;
    int t;
    //cin >> t;
    t = 1;
    while(t--){
        run_case();
    }
}

/*
    NEVER GIVE UP!
    DOING SMTHNG IS BETTER THAN DOING NTHNG!!!
    Your Guide when stuck:
    - Continue keyword only after reading the whole input
    - Don't use memset with testcases
    - Check for corner cases(n=1, n=0)
    - Check where you declare n(Be careful of declaring it globally and in main)
*/

Compilation message (stderr)

passport.cpp: In function 'void usaco_problem()':
passport.cpp:32:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |     freopen("milkvisits.in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
passport.cpp:33:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |     freopen("milkvisits.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
passport.cpp: In function 'void init()':
passport.cpp:39:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   39 | freopen("input.txt", "r", stdin);
      | ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
passport.cpp:41:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 | freopen("output.txt", "w", stdout);
      | ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 0 / 16
• Subtask 3: 0 / 24
• Subtask 4: 0 / 8
• Subtask 5: 0 / 46