Submission #1027922

#	Time	Username	Problem	Language	Result	Execution time	Memory
1027922		Issa	Flooding Wall (BOI24_wall)	C++17	0 / 100	5 ms	23948 KiB

Main

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define ent "\n"

const int maxn = 1e6 + 100;
const ll INF = (ll)1e18 + 100;
const int inf = 1e9 + 100;
const int MOD = 1e9 + 123;
const int maxl = 26;
const int P = 31;

int n;
int a[maxn][2];
vector<int> dp[maxn];

void test(){
	cin >> n;
	vector<int> s = {-1};
	for(int i = 1; i <= n; i++){
		cin >> a[i][0];
	}
	for(int i = 1; i <= n; i++){
		cin >> a[i][1];
		s.push_back(a[i][0]);
		s.push_back(a[i][1]);
	}
	sort(s.begin(), s.end());
	s.resize(unique(s.begin(), s.end()) - s.begin());
	for(int i = 1; i <= n; i++){
		a[i][0] = lower_bound(s.begin(), s.end(), a[i][0]) - s.begin();
		a[i][1] = lower_bound(s.begin(), s.end(), a[i][1]) - s.begin();
		if(a[i][0] > a[i][1]) swap(a[i][0], a[i][1]);
	}
	dp[0] = vector<int>(s.size(), 0);
	dp[0][0] = 1;
	for(int i = 1; i <= n; i++){
		dp[i] = dp[i-1];
		for(int j = s.size()-1; j >= 0; j--){
			if(s[j] > a[i][1]){
				dp[i][j] = dp[i][j] * 2 % MOD;
			} else if(s[j] > a[i][0]){
				dp[i][a[i][1]] = (dp[i][a[i][1]] + dp[i-1][j]) % MOD;
			} else{
				dp[i][a[i][1]] = (dp[i][a[i][1]] + dp[i-1][j]) % MOD;
				dp[i][a[i][0]] = (dp[i][a[i][0]] + dp[i-1][j]) % MOD;
				dp[i][j] = 0;
			}
		}
	}
	vector<int> d = vector<int>(s.size(), 0);
	d[0] = 1; ll ans = 0;
	for(int i = n; i > 0; i--){
		ll sum1 = 0, sum2 = 0;
		for(int j = s.size() - 1; j >= 0; j--){
			sum1 = (sum1 + dp[i-1][j]) % MOD;
			ll cnt = (1ll * d[j] * sum1 + dp[i-1][j] * sum2) % MOD;
			sum2 = (sum2 + d[j]) % MOD;
			if(s[j] > a[i][1]){
				ans = (ans + 1ll * (s[j] - a[i][1]) * cnt) % MOD;
			} if(s[j] > a[i][0]){
				ans = (ans + 1ll * (s[j] - a[i][0]) * cnt) % MOD;
			}
		}
		for(int j = s.size()-1; j >= 0; j--){
			if(s[j] > a[i][1]){
				d[j] = d[j] * 2 % MOD;
			} else if(s[j] > a[i][0]){
				d[a[i][1]] = (d[a[i][1]] + d[j]) % MOD;
			} else{
				d[a[i][1]] = (d[a[i][1]] + d[j]) % MOD;
				d[a[i][0]] = (d[a[i][0]] + d[j]) % MOD;
				d[j] = 0;
			}
		}
	}
	cout << ans;
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int t; t = 1;
    while(t--) test();
    cout << ent;
}

• Subtask 1: 0 / 8
• Subtask 2: 0 / 17
• Subtask 3: 0 / 19
• Subtask 4: 0 / 14
• Subtask 5: 0 / 12
• Subtask 6: 0 / 30