Submission #1273839

#	Time	Username	Problem	Language	Result	Execution time	Memory
1273839		icebear	Trains (BOI24_trains)	C++20	100 / 100	240 ms	120956 KiB

Main

// ~~ icebear ~~
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;

template<class T>
    bool minimize(T &a, const T &b) {
        if (a > b) return a = b, true;
        return false;
    }
    
template<class T>
    bool maximize(T &a, const T &b) {
        if (a < b) return a = b, true;
        return false;
    }
    
#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "cuuho"

const int MOD = 1e9 + 7;
const int inf = 1e9 + 27092008;
const ll INF = 1e18 + 27092008;
const int N = 1e5 + 5;
const int S = 300;
int n, d[N], x[N], dp[N], pref[N][S + 5];

void init(void) {
    cin >> n;
    FOR(i, 1, n) cin >> d[i] >> x[i];
}

void process(void) {
    dp[1] = 1;
    FOR(i, 1, n) {
        FOR(j, 1, S) if (i >= j) {
            (pref[i][j] += pref[i - j][j]) %= MOD;
            (dp[i] += pref[i][j]) %= MOD;
        }

        if (d[i] <= S && i + d[i] <= n) {
            (pref[i][d[i]] += dp[i]) %= MOD;
            ll e = i + 1LL * d[i] * (x[i] + 1);
            if (e <= n) pref[e][d[i]] = (pref[e][d[i]] - dp[i] + MOD) % MOD;
        } else {
            FOR(j, 1, x[i]) {
                if (i + j * d[i] > n) break;
                (dp[i + j * d[i]] += dp[i]) %= MOD;
            }
        }
    }
    int ans = 0;
    FOR(i, 1, n) (ans += dp[i]) %= MOD;
    cout << ans;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int tc = 1;
//     cin >> tc;
    while(tc--) {
        init();
        process();
    }
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:74:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:75:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   75 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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