Submission #118749

#	Time	Username	Problem	Language	Result	Execution time	Memory
118749		silxikys	Calvinball championship (CEOI15_teams)	C++14	20 / 100	227 ms	1536 KiB

teams

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

const int maxn = 1e4+4, M = 1e9+7;
int n, a[maxn];
int dp[2][maxn];

void madd(int& a, int b) {
	a = (a+b) % M;
}
int mult(int a, int b) {
	return (1LL*a*b) % M;
}

struct Node {
	int s, e, m;
	//covers s,e;
	int sum;
	int maxi;
	Node *l, *r;
	
	Node(int a, int b) {
		s = a;
		e = b;
		sum = 0;
		maxi = 0;
		if (s != e) {
			m = (s+e)/2;
			l = new Node(s,m);
			r = new Node(m+1,e);
		}
		else {
			l = NULL;
			r = NULL;
		}
	}


	void add(int i, int x) {
		if (s == e) {
			sum += x;
			maxi = sum;
			return;
		}
		if (i <= m) {
			l->add(i,x);
		}
		else if (i > m) {
			r->add(i,x);
		}
		else assert(false);
		sum = l->sum + r->sum;
		maxi = max(l->maxi,r->maxi);
	}

	int getmaxi(int st, int en) {
		if (st <= s && e <= en) {
			return maxi;
		}
		int ret = 0;
		if (st <= m) {
			ret = max(ret,l->getmaxi(st,en));
		}
		if (en > m) {
			ret = max(ret,r->getmaxi(st,en));
		}
		return ret;
	}	

	int getsum(int st, int en) {
		if (st <= s && e <= en) {
			return sum;
		}
		int ret = 0;
		if (st <= m) {
			ret += l->getsum(st,en);
		}
		if (en > m) {
			ret += r->getsum(st,en);
		}
		return ret;
	}
};

int br = 0;
void DFS(vector<int> v) {
    if (v.size() == n) {
        bool poss = true;
        int biggestSeen = 0;
        for (int i: v) {
            if (i > biggestSeen+1) {
                poss = false;
                break;
            }
            biggestSeen = max(biggestSeen,i);
        }
        if (poss) {
            br++;
            /*
            for (int i: v) {
                cout << i << ' ';
            }
            cout << '\n';
            */
        }
    }
    else {
        for (int j = 1; j <= n; j++) {
            v.push_back(j);
            DFS(v);
            v.pop_back();
        }
    }
}
 
int brute() {
    vector<int> v;
    DFS(v);
    return br;
}

int main()
{
    ios_base::sync_with_stdio(false); cin.tie(0);
    cin >> n;
    Node *root = new Node(0,n);
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        root->add(i,a[i]);
    }
    for (int i = 1; i <= n+1; i++) {
    	dp[0][i] = 1;
    }

    int ans = 0;
    for (int i = n; i >= 1; i--) {
    	for (int j = 1; j <= i; j++) {
    		dp[1][j] = (mult(j,dp[0][j]) + dp[0][j+1]) % M;
    		//cout << dp[0][j] << ' ';
    	}
    	//cout << '\n';
    	int m = root->getmaxi(0,i-1);
        if (m < a[i]) {
            madd(ans,mult(m,dp[0][m]));
        }
        else {
            madd(ans,mult(a[i]-1,dp[0][m]));
        }
        //cout << i << ": " << mult(a[i]-1,dp[0][m]) << '\n';

    	for (int j = 1; j <= n; j++) {
    		dp[0][j] = dp[1][j];
    	}
    }

    cout << ((ans+1)%M) << '\n';
    //cout << "brute : " << brute() << '\n';
}

Compilation message (stderr)

teams.cpp: In function 'void DFS(std::vector<int>)':
teams.cpp:88:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if (v.size() == n) {
         ~~~~~~~~~^~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10