Submission #1279203

#	Time	Username	Problem	Language	Result	Execution time	Memory
1279203		vuquangsang	Trains (BOI24_trains)	C++20	100 / 100	235 ms	124872 KiB

Main

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

#define     el "\n"
#define     FOR(i,a,b) for(int i = (a), _b = (b); i <= _b; i++)
#define     FORD(i,a,b) for(int i = (a), _b = (b); i >= _b; i--)
#define     pb push_back
#define     fi first
#define     se second
#define     all(x) x.begin(),x.end()
#define     lg(x) __lg(x)
#define     alla(a,n) a+1,a+n+1
#define     ll long long


template <class T> bool maxi(T &x, T y) { if(x < y) { x = y ; return true ;} return false;}
template <class T> bool mini(T &x, T y) { if(x > y) { x = y ; return true ;} return false;}

const int sm = 1e9 + 7;
const int N = 1e5 + 2;

int n, x[N], d[N];

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

/* Try your best
    No regrets */
void add(int &x, int y)
{
    x += y;
    if(x >= sm) x -= sm;
    if(x < 0) x += sm;
}
namespace subtask_1
{
    int dp[N];

    void slv()
    {
        dp[1] = 1;
        FOR(i, 1, n - 1) if(d[i]) {
            FOR(t, 1, x[i]) {
                int far = i + d[i] * t;
                if(far > n) break;
                add(dp[far], dp[i]);
            }
        }
        int ans = 0;
        FOR(i, 1, n) add(ans, dp[i]);
        cout << ans;
    }
}

namespace subtask_3
{
    bool check_sub()
    {
        FOR(i, 1, n) if(d[i] > 1) return 0;
        return 1;
    }

    int dp[N];
    int st[4 * N], lz[4 * N];

    void down(int id)
    {
        if(lz[id]) {
            int val = lz[id];
            add(st[id << 1], val); add(st[id << 1 | 1], val);
            add(lz[id << 1], val); add(lz[id << 1 | 1], val);
            lz[id] = 0;
        }
    }
    void upd(int id, int l, int r, int u, int v, int val)
    {
        if(r < u || v < l) return;
        if(u <= l && r <= v) {
            add(st[id], val);
            add(lz[id], val);
            return;
        }
        int mid = (r + l) >> 1;
        down(id);
        upd(id << 1, l, mid, u, v, val);
        upd(id << 1 | 1, mid + 1, r, u, v, val);
        st[id] = max(st[id << 1], st[id << 1 | 1]);
    }
    int get(int id, int l, int r, int pos)
    {
        if(pos > r || pos < l) return 0;
        if(l == r) return st[id];
        int mid = (r + l) >> 1;
        down(id);
        return max(get(id << 1, l, mid, pos), get(id << 1 | 1, mid + 1, r, pos));
    }
    void slv()
    {
        dp[1] = 1;
        upd(1, 1, n, 1, 1, dp[1]);
        FOR(i, 1, n) {
            dp[i] = get(1, 1, n, i);
            upd(1, 1, n, i + 1, min(n, i + x[i]), dp[i]);
        }

        int ans = 0;
        FOR(i, 1, n) add(ans, dp[i]);
//        FOR(i, 1, n) cout << dp[i] << " "; cout << el;

        cout << ans;
    }
}

namespace subtask_5
{
    const int BLOCK = 315;

    int dp[N], uwu[N][BLOCK];
    void slv()
    {
        dp[1] = 1;
        int ans = 0;
        FOR(i, 1, n) {

            for(int j = 1; j < BLOCK; j++) {
                if(i >= j) add(uwu[i][j], uwu[i - j][j]);
                add(dp[i], uwu[i][j]);
            }
            add(ans, dp[i]);

            if(d[i] == 0) continue;
            if(d[i] >= BLOCK) {
                FOR(t, 1, x[i]) {
                    int far = i + t * d[i];
                    if(far > n) break;
                    add(dp[far], dp[i]);
                }
            }
            else {
                if(i + d[i] > n) continue;

                int l = i + d[i];
                int r = i + min((n - i) / d[i], x[i]) * d[i];
                add(uwu[l][d[i]], dp[i]);
                if(r + d[i] <= n) {
                    add(uwu[r + d[i]][d[i]], - dp[i]);
                }
            }
        }
        cout << ans;
    }
}
/* Code slowly, think carefully */

main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);

    #define __Azul__ "task"
    if(fopen(__Azul__".inp", "r")) {
        freopen(__Azul__".inp", "r", stdin);
        freopen(__Azul__".out", "w", stdout);
    }

    bool qs = 0;

    int T = 1;
    if(qs) cin >> T;
    while(T--) {
        inp();
        subtask_5::slv();
    }

    cerr << "\nTime" << 0.001 * clock() << "s "; return 0;


}

Compilation message (stderr)

Main.cpp:158:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  158 | main()
      | ^~~~
Main.cpp: In function 'int main()':
Main.cpp:164:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  164 |         freopen(__Azul__".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:165:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  165 |         freopen(__Azul__".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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