Submission #1023491

#	Time	Username	Problem	Language	Result	Execution time	Memory
1023491		hackermub	Boat (APIO16_boat)	C++17	0 / 100	263 ms	524288 KiB

boat

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

#define int long long
#define pii pair<int,int>
#define vvi vector<vector<int>>
#define sz(v) (int)v.size()
#define all(v) v.begin(),v.end()
#define bruh cout<<"\nbruh\n"; exit(0);

#ifndef debug
#define debug(...)
#endif

const int MOD = 1e9 + 7;

int add(int a, int b){
    int ans = (a % MOD + b % MOD) % MOD;
    while(ans < 0) ans += MOD;
    return ans;
}

int mul(int a, int b){
    int ans = (a % MOD * b % MOD) % MOD;
    while(ans < 0) ans += MOD;
    return ans;
}

// a^-1 = binpow(a, MOD - 2);
int binpow(int b, int p){
    int ans = 1;
    b %= MOD;
    while(p > 0){
        if(p & 1) ans = mul(ans, b);
        b = mul(b, b);
        p /= 2;        
    }
    return ans;
}

int compress(vector<pii>& v){
	vector<int> val;
	for(auto [a, b] : v){
		if(!a) continue;
		val.push_back(a);
		val.push_back(b);
	}
	sort(all(val));
	val.erase(unique(all(val)));
	for(auto& [a, b] : v){
		if(!a) continue;
		a = lower_bound(all(val), a) - val.begin() + 1;
		b = lower_bound(all(val), b) - val.begin() + 1;
	}
	return val.back();
}

void solve(){
	int n;
	cin >> n;
	vector<pii> v(n + 1);
	for(int i = 1; i <= n; i++){
		cin >> v[i].first >> v[i].second;
	}
	int MX = compress(v);
	// debug(v, MX);

	int dp[n + 1][MX + 1];
	memset(dp, 0, sizeof(dp));
	dp[0][0] = 1;
	for(int i = 1; i <= n; i++){
		for(int j = v[i].first; j <= v[i].second; j++){
			for(int k = 0; k < i; k++){
				for(int l = v[k].first; l <= min(j - 1, v[k].second); l++){
					dp[i][j] = add(dp[i][j], dp[k][l]);
					// debug(i, j, dp[i][j]);
				}
			}
		}
	}
	int ans = 0;
	for(int i = 1; i <= n; i++){
		for(int j = v[i].first; j <= v[i].second; j++){
			ans = add(ans, dp[i][j]);
		}
	}
	cout << ans << "\n";
} 



int32_t main(){
    ios_base::sync_with_stdio(false);cin.tie();
    int T = 1;
    // cin>>T;
    for(int ti = 1; ti <= T; ti++){
        // cout<< "Case "<<ti<<":\n";
        solve();

    }
    return 0;
}

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