Submission #1303466

#	Time	Username	Problem	Language	Result	Execution time	Memory
1303466		nanaseyuzuki	Trains (BOI24_trains)	C++20	16 / 100	121 ms	4768 KiB

Main

#include <bits/stdc++.h>
// Kazusa_Megumi
#define ll long long
#define fi first
#define se second
#define pii pair<int, int>
#define all(a) a.begin(), a.end()
using namespace std;

const int mn = 5e5 + 5, mod = 1e9 + 7, inf = 2e9, B = 317;

int n, x[mn], d[mn], dp[mn], val[B + 5][B + 5];
vector <int> ed[mn];

void solve() {
    cin >> n;
    dp[1] = 1;
    for(int i = 1; i <= n; i++){
    	cin >> d[i] >> x[i];
    	if(d[i] && d[i] <= B){
    		int final = min(i + x[i] * d[i] + 1, n + 1);
    		// cerr << i << ' ' << final << '\n';
    		ed[final].push_back(i);
    	}
    }

    for(int i = 1; i <= n; i++){
    	for(auto j : ed[i]){
    		int y = d[j];
    		val[y][j % y] = ((val[y][j % y] - dp[j]) % mod + mod) % mod;
    	}
    	for(int j = 1; j <= B; j++) dp[i] = (dp[i] + val[j][i % j]) % mod;

    	if(d[i] > B){
    		for(int j = 1; j <= x[i]; j++){
    			int nxt = i + j * d[i];
    			if(nxt > n) break;
    			dp[nxt] = (dp[nxt] + dp[i]) % mod;
    		}
    	}
    	else{
    		if(d[i] == 0) continue;
    		val[d[i]][i % d[i]] = (val[d[i]][i % d[i]] + dp[i]) % mod;
    	}
    }

    int res = 0;
    for(int i = 1; i <= n; i++) res = (res + dp[i]) % mod;
    cout << res << '\n';
}

main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    if (fopen("Kazuki.INP", "r")) {
        freopen("Kazuki.INP", "r", stdin);
        freopen("Kazuki.OUT", "w", stdout);
    }
    int t = 1;
    // cin >> t;
    while (t--) solve();
    return 0;
}

Compilation message (stderr)

Main.cpp:52:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   52 | main() {
      | ^~~~
Main.cpp: In function 'int main()':
Main.cpp:56:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   56 |         freopen("Kazuki.INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:57:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |         freopen("Kazuki.OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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