Submission #677666

#	Time	Username	Problem	Language	Result	Execution time	Memory
677666		Cross_Ratio	Seesaw (JOI22_seesaw)	C++14	67 / 100	215 ms	33064 KiB

seesaw

#include <bits/stdc++.h>
#define int long long
#define double long double
using namespace std;
int A[200005];
int B[200005];
int N;
vector<double> V[200005];
int sum(int x, int y) {
    return B[y] - (x?B[x-1]:0);
}
typedef pair<int,int> P;
typedef pair<double, pair<int,int>> PP;
signed main() {
    cin.sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> N;
    int i, j;
    for(i=0;i<N;i++) cin >> A[i];
    for(i=0;i<N;i++) {
        B[i] = (i?B[i-1]:0)+A[i];
    }
    int s1 = 0, e1 = N-1, s2 = 0, e2 = N-1;
    V[N].push_back((double)B[N-1]/N);
    for(i=N-1;i>=1;i--) {
        if(sum(s1+1, e1)*N < B[N-1]*i) {
            s1++;
        }
        else e1--;
        if(sum(s2, e2-1)*N > B[N-1]*i) {
            e2--;
        }
        else s2++;
        for(j=s1;j<=s2;j++) {
            V[i].push_back((double)sum(j, j+i-1) / i);
        }
    }
    set<PP> S;
    for(i=1;i<=N;i++) {
        S.insert(PP(V[i][0], P(i, 0)));
    }
    double ans = 1e9;
    while(true) {
        double mi = S.begin()->first;
        double ma = S.rbegin()->first;
        ans = min(ans, ma - mi);
        PP k = *S.begin();
        auto it = S.begin();
        S.erase(it);
        int k1 = k.second.first, k2 = k.second.second;
        if(k2+1>=V[k1].size()) break;
        S.insert(PP(V[k1][k2+1], P(k1, k2)));
    }
    cout << fixed << setprecision(15) << ans;
}

Compilation message (stderr)

seesaw.cpp: In function 'int main()':
seesaw.cpp:52:16: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long double>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   52 |         if(k2+1>=V[k1].size()) break;
      |            ~~~~^~~~~~~~~~~~~~

• Subtask 1: 1 / 1
• Subtask 2: 33 / 33
• Subtask 3: 33 / 33
• Subtask 4: 0 / 33