Submission #1002016

#	Time	Username	Problem	Language	Result	Execution time	Memory
1002016		LOLOLO	Trains (BOI24_trains)	C++17	100 / 100	138 ms	132180 KiB

Main

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
 
#define           f     first
#define           s     second
#define           pb    push_back
#define           ep    emplace
#define           eb    emplace_back
#define           lb    lower_bound
#define           ub    upper_bound
#define       all(x)    x.begin(), x.end()
#define      rall(x)    x.rbegin(), x.rend()
#define   uniquev(v)    sort(all(v)), (v).resize(unique(all(v)) - (v).begin())
#define     mem(f,x)    memset(f , x , sizeof(f))
#define        sz(x)    (ll)(x).size()
#define  __lcm(a, b)    (1ll * ((a) / __gcd((a), (b))) * (b))
#define          mxx    *max_element
#define          mnn    *min_element
#define    cntbit(x)    __builtin_popcountll(x)
#define       len(x)    (int)(x.length())
 
const int N = 1e5 + 10;
const int L = sqrt(N) + 10;
ll d[N], x[N];
int dp[N], mod = 1e9 + 7;
int f[N][L + 1];

ll solve() {
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++)
        cin >> d[i] >> x[i];

    for (int i = n; i >= 1; i--) {
        if (d[i] <= L) {
            if (d[i] && x[i]) {
                ll st = i + d[i];
                ll en = i + (x[i] + 1) * d[i];
                if (en <= n) {
                    dp[i] = f[st][d[i]] - f[en][d[i]];  
                } else {
                    dp[i] = f[st][d[i]];
                }
            }
        } else {
            for (int j = 1; j <= x[i] && j * d[i] + i <= n; j++)
                dp[i] = (dp[i] + dp[j * d[i] + i]) % mod;
        }

        dp[i]++;

        while (dp[i] < 0)
            dp[i] += mod;

        for (int j = 1; j <= L; j++) {
            f[i][j] = dp[i];
            if (i + j <= n)
                f[i][j] = (dp[i] + f[i + j][j]) % mod;
        }
    }

    return dp[1];
}
 
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
 
 
    int t = 1;
    //cin >> t;
 
    while (t--) {
        cout << solve() << '\n';
    }
 
    return 0;
} 

• Subtask 1: 8 / 8
• Subtask 2: 13 / 13
• Subtask 3: 16 / 16
• Subtask 4: 34 / 34
• Subtask 5: 29 / 29