Submission #320165

#	Time	Username	Problem	Language	Result	Execution time	Memory
320165		Karen124	MP3 Player (CEOI10_mp3player)	C++14	20 / 100	89 ms	1124 KiB

mp3player

#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define ll long long int 
#define F first
#define S second
#define pb push_back
const ll N = 1e5 + 5;
const ll LOG = 30;
const ll MOD = 1e9 + 7;
const ll INF = 2e9 + 10;
int n, Vmax, V2, a[N], t[N], dif;
int R_Do_Operations(int e, int T){
    for (int i = n; i >= 2; i--){
        if (t[i] - t[i - 1] <= T){
            e -= a[i];
        }
        e = max(e, 0);
        e = min(e, Vmax);
    }
    return e;
}
int Do_Operations(int s, int T){
    for (int i = 2; i <= n; i++){
        if (t[i] - t[i - 1] <= T){
            s += a[i];
        }
        s = max(s, 0);
        s = min(s, Vmax);
    }  
    return s;
}
int ok(int T){
    int s = R_Do_Operations(V2, T);
    int e = Do_Operations(s, T);
    return (e == V2);
}
int main (){
    cin >> n >> Vmax >> V2;
    for (int i = 1; i <= n; i++){
        char c;
        cin >> c >> t[i];
        a[i] = ((c == '+') ? 1 : -1);
        if (i != 1) dif = max(dif, t[i] - t[i - 1]);
    }
    int en = V2; 
    for (int i = n; i >= 1; i--){
        en -= a[i];
        en = max(en, 0);
        en = min(en, Vmax);
    }
    for (int i = 1; i <= n; i++){
        en += a[i];
        en = max(en, 0);
        en = min(en, Vmax);
    }
    if (en == V2){
        cout << "infinity\n";
        return 0;
    }
    int l = 0, r = INF;
    while (dif < l){
    }
    while (l + 1 < r){
        int mid = (l + r) / 2;
        if (ok(mid)) l = mid;
        else r = mid;
    }
    int L = R_Do_Operations(V2, l), R = Vmax + 1;
    while (L + 1 < R){
        int mid = (L + R) / 2;
        if (Do_Operations(mid, l) == V2) L = mid;
        else R = mid;
    }
    cout << l << ' ' << L << '\n';
    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 10
• Subtask 3: 10 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10