Submission #946526

#	Time	Username	Problem	Language	Result	Execution time	Memory
946526		n3rm1n	Boat (APIO16_boat)	C++17	31 / 100	1932 ms	524288 KiB

boat

/// boat
#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
const int MAXN = 505, MAXX = 1e6+10;
void speed()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}
int n, m;
int a[MAXN], b[MAXN];
unordered_map < int, int > id;
vector < int > g, u;
void read_hash()
{
    cin >> n;
    for (int i = 1; i <= n; ++ i)
    {
        cin >> a[i] >> b[i];
        for (int j = a[i]; j <= b[i]; ++ j)
            g.push_back(j);
    }
    sort(g.begin(), g.end());
    u.push_back(g[0]);
    for (int i = 1; i < g.size(); ++ i)
    {
        if(u.back() != g[i])
            u.push_back(g[i]);
    }
    for (int i = 0; i < u.size(); ++ i)
    {
        id[u[i]] = i+1;
    }
}

int dp[MAXX];
const int mod = 1e9 + 7;
int pref[MAXX];
void solve()
{
    int ans = 0;
    int maxx = u.size();
    for (int i = 1; i <= n; ++ i)
    {

        for (int j = id[b[i]]; j >= id[a[i]]; -- j)
        {
            dp[j] += pref[j-1] + 1;
            dp[j] %= mod;
        }
        for (int j = id[a[i]]; j <= u.size(); ++ j)
            pref[j] = (pref[j-1] + dp[j]) % mod;

    }

    ans = pref[maxx];
    ans %= mod;
    cout << ans << endl;
}
int main()
{
    speed();

    read_hash();
    solve();
    return 0;
}

Compilation message (stderr)

boat.cpp: In function 'void read_hash()':
boat.cpp:27:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |     for (int i = 1; i < g.size(); ++ i)
      |                     ~~^~~~~~~~~~
boat.cpp:32:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   32 |     for (int i = 0; i < u.size(); ++ i)
      |                     ~~^~~~~~~~~~
boat.cpp: In function 'void solve()':
boat.cpp:53:34: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |         for (int j = id[a[i]]; j <= u.size(); ++ j)
      |                                ~~^~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 22 / 22
• Subtask 3: 0 / 27
• Subtask 4: 0 / 42