Submission #995349

#	Time	Username	Problem	Language	Result	Execution time	Memory
995349		Lobo	Trains (BOI24_trains)	C++17	0 / 100	2 ms	6748 KiB

Main

#include<bits/stdc++.h>
using namespace std;
const long long inf = 1e18 + 10;
const int inf1 = 1e9 + 10;
#define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
const int maxn = 1e5+10;
const int B = 500;
const int mod = 1e9+7;

int n, d[maxn], x[maxn], dp[maxn], tran1[maxn][B+1];
vector<int> tran2[maxn];

void solve() {
    cin >> n;
    for(int i = 1; i <= n; i++) {
    	cin >> d[i] >> x[i];
    	if(d[i] == 0 or x[i] == 0) continue;

    	if(d[i] > B) {
    		for(int j = 1; j <= x[i] && i+j*d[i] <= n; j++) {
    			tran2[i+(j-1)*d[i]].pb(i+j*d[i]);
    		}
    	}
    	else if(i+d[i] <= n) {
    		tran1[i][d[i]] = x[i];
    	}
    }


    dp[1] = 1;
    vector<int> fq(n+1,0);
    int ans = 0;
    for(int i = 1; i <= n; i++) {
    	for(auto j : tran2[i]) {
    		if(fq[j]) continue;
    		fq[j] = 1;
    		dp[j] = (dp[j]+dp[i])%mod;
    	}
    	for(auto j : tran2[i]) {
    		fq[j] = 0;
    	}

    	for(int dif = 1; dif <= B; dif++) {
    		if(tran1[i][dif] != 0) {
    			dp[i+dif] = (dp[i+dif]+dp[i])%mod;
    			tran1[i+dif][dif] = max(tran1[i+dif][dif],tran1[i][dif]-1);
    		}
    	}
    	ans = (ans+dp[i])%mod;
    }

    cout << ans << endl;
}

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(0);

    #ifndef ONLINE_JUDGE
    freopen("in.in", "r", stdin);
    freopen("out.out", "w", stdout);
    #endif

    int tt = 1;
    // cin >> tt;
    while(tt--) {
        solve();
    }

}

Compilation message (stderr)

Main.cpp: In function 'int32_t main()':
Main.cpp:67:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   67 |     freopen("in.in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
Main.cpp:68:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |     freopen("out.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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