Submission #1263329

#	Time	Username	Problem	Language	Result	Execution time	Memory
1263329		vidux	Trains (BOI24_trains)	C++17	71 / 100	2105 ms	633928 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define SINGLE_TEST 1

typedef long long ll;
typedef unsigned long long ull; 
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;

#define FOR(i, n) for (int(i) = 0; (i) < (n); ++(i))
#define REP(i, k, n) for (int(i) = (k); (i) <= (n); ++(i))
#define REPR(i, k, n) for (int(i) = (k); (i) >= (n); --(i))
#define FORR(x, arr) for (auto &x : arr)
#define FORR2(x, y, arr) for (auto &[x, y] : arr)
#define ALL(a) (a.begin()), (a.end())
#define RALL(a) (a.rbegin()), (a.rend())
#define REVERSE(v) reverse(ALL(v))
#define SZ(x) (int)(x).size()
#define fi first
#define se second
#define debug(x) cerr << #x << " = " << (x) << endl

const int MOD = 1e9 + 7;
const int INF = 1e9;
const ll LLINF = 1e18;

void solve() {
	int n; cin >> n;
	vl d(n), x(n);
	FOR(i, n) cin >> d[i] >> x[i];
	vector<unordered_map<int, ll>> v(n);
	vector<unordered_map<int, ll>> r(n);
	vl ways(n);
	ways[0] = 1;
	ll ans = 0;
	FOR(i, n) {
		ans = (ans + ways[i]) % MOD;
		if (x[i] && d[i]) { 
			v[i][d[i]] = (v[i][d[i]]+ways[i])%MOD;
			ll e = i+d[i]*(x[i]+1);
			if (e < (ll)n) {
				v[e][d[i]] = (v[e][d[i]]-ways[i]+MOD)%MOD;
				ways[e] = (ways[e]-ways[i]+MOD)%MOD;
			}
		}
		FORR2(len, cnt, v[i]) if (cnt && i+len < n) {
			v[i+len][len] = (v[i+len][len]+cnt)%MOD;
			ways[i+len] = (ways[i+len]+cnt)%MOD;
		}
	}
	cout << ans << endl;
}

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);

#if SINGLE_TEST
	solve();
#else
	int t;
	cin >> t;
	while (t--) {
		solve();
	}
#endif

	return 0;
}

• Subtask 1: 8 / 8
• Subtask 2: 13 / 13
• Subtask 3: 16 / 16
• Subtask 4: 34 / 34
• Subtask 5: 0 / 29