Submission #672247

#	Time	Username	Problem	Language	Result	Execution time	Memory
672247		Dan4Life	Boat (APIO16_boat)	C++17	9 / 100	2077 ms	524288 KiB

boat

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define fi first
#define se second
const int maxn = 5e2+10;
const int MOD = (int)1e9+7;
pair<int,int> a[maxn];
unordered_map<int,int> dp[maxn];
int n;

int32_t main() {
	cin >> n; int ans = 0;
	for(int i = 0; i < n; i++) cin >> a[i].fi >> a[i].se;
	for(int i = 0; i < n; i++){
		for(int j = a[i].fi; j <= a[i].se; j++){
			dp[i][j]=1; 
			if(j>a[i].fi) dp[i][j]+=dp[i][j-1];
			if(dp[i][j]>MOD) dp[i][j]-=MOD;
			
			for(int k = 0; k < i; k++){
				if(j>a[k].fi) dp[i][j]+=dp[k][min(j-1,a[k].se)];
				if(dp[i][j]>MOD) dp[i][j]-=MOD;
			}
		}
	}
	for(int i = 0; i < n; i++) ans+=dp[i][a[i].se], ans-=(ans>MOD?MOD:0);
	cout << ans;
}

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