Submission #405820

#	Time	Username	Problem	Language	Result	Execution time	Memory
405820		gevacrt	Boat (APIO16_boat)	C++17	0 / 100	483 ms	524292 KiB

boat

#include<bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp> 
using namespace __gnu_pbds; 

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

typedef vector<int> vi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vii> vvii;

#define INF INT_MAX
#define MOD 1000000007
#define all(x) x.begin(), x.end()

vii A;
vector<gp_hash_table<int, ll>> dp;

void solve(int x, int C){
    auto &v = dp[x][C];
    if(x == 0) v = 2;
    else{
        v += dp[x-1][min(C-1, A[x-1].second)]; v %= MOD;
        v += dp[x-1][min(C, A[x-1].second)]; v %= MOD;
    }

    if(dp[x].find(C-1) != dp[x].end()){
        v += dp[x][C-1]; v %= MOD;
        if(x == 0) v -= 1, v %= MOD;
        else v -= dp[x-1][min(C-1, A[x-1].second)], v %= MOD;
    }
}

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

    int N; cin >> N;
    A.resize(N);
    for(auto &[l, r] : A)
        cin >> l >> r;    
    
    dp.resize(N);

    for(int x = 0; x < N; x++){
        for(auto [l, r] = A[x]; l <= r; l++)
            solve(x, l);
    }

    cout << (dp[N-1][A.back().second]-1+MOD)%MOD << endl;

    return 0;
}

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