Submission #489645

#	Time	Username	Problem	Language	Result	Execution time	Memory
489645		Yuisuyuno	Balloons (CEOI11_bal)	C++14	20 / 100	3 ms	460 KiB

bal

//Nguyen Huu Hoang Minh
#include <bits/stdc++.h>
#define sz(x) int(x.size())
#define all(x) x.begin(),x.end()
#define reset(x) memset(x, 0,sizeof(x))
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define N 2005
#define remain(x) if (x > MOD) x -= MOD
#define ii pair<int, int>
#define iiii pair< ii , ii >
#define viiii vector< iiii >
#define vi vector<int>
#define vii vector< ii >
#define bit(x, i) (((x) >> (i)) & 1)
#define Task "test"
#define int long long

using namespace std;

typedef long double ld;
const int inf = 1e10;
const int minf = -1e10;

int n;
double x[N], r[N];
double R[N];

void readfile()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    if (fopen(Task".inp","r"))
    {
        freopen(Task".inp","r",stdin);
        //freopen(Task".out","w",stdout);
    }
    cin >> n;
    for(int i=1; i<=n; i++){
        cin >> x[i] >> r[i];
    }
}

double check(int pos, int pre){
    //(x[pre],R[pre])
    //(x[pos],R[pos])
    //dis*dis = (xpre-xpos)*(xpre-xpos) + (Rpre-R)*(Rpre-R) = Rpre^2 + 2*Rpre*R + R^2
    //(xpre-xpos)*(xpre-xpos) = 4*Rpre*R
    double R_cur = (x[pre]-x[pos])*(x[pre]-x[pos])/4/R[pre];
    return R_cur;
}

void proc()
{
    R[1] = r[1];
    stack<int> st;
    st.push(1);
    for(int i=2; i<=n; i++){
        double RR;
        while (st.size()){
            int id = st.top();
            double xi = x[id];
            double ri = R[id];
            RR = min(r[i],(xi-x[i])*(xi-x[i])/4/ri);
            if (RR > ri+1e-9) st.pop();
            else break;
        }
        st.push(i);
        R[i] = RR;
    }
    cout << setprecision(3) << fixed;
    for(int i=1; i<=n; i++) cout<<R[i]<<'\n';
}

signed main()
{
    readfile();
    proc();
    return 0;
}

Compilation message (stderr)

bal.cpp: In function 'void readfile()':
bal.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen(Task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
bal.cpp: In function 'void proc()':
bal.cpp:71:14: warning: 'RR' may be used uninitialized in this function [-Wmaybe-uninitialized]
   71 |         R[i] = RR;
      |         ~~~~~^~~~

• 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