Submission #1268764

#	Time	Username	Problem	Language	Result	Execution time	Memory
1268764		hoa208	Sure Bet (CEOI17_sure)	C++20	100 / 100	57 ms	3400 KiB

sure

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; i++)
#define FORD(i, b, a) for (int i = (b), _a = (a); i >= _a; i--)
#define pa pair<ll, ll>
#define fi first
#define se second
#define bit(mask, j) ((mask >> j) & 1)
const   ll mod = 1e9 + 7;
const   ll INF = 1e18;
//--------------------------------------------------------------------
const ll N = 1e5 + 10;
double a[N], b[N], sufa[N], sufb[N];
double ans = 0.0;
void hbmt() {
    ll n;
    cin >> n;
    FOR(i, 1, n) {
        double x, y;
        cin >> x >> y;
        a[i] = x;
        b[i] = y;
    }
    sort(a + 1, a + n + 1);
    sort(b + 1, b + n + 1);
    FORD(i, n, 1) {
        sufa[i] = sufa[i + 1] + a[i];
        sufb[i] = sufb[i + 1] + b[i];

    }
    FORD(i, n, 1) {
        double X = sufa[i];
        ll l = 1, r = n, res = -1;
        while(l <= r) {
            ll mid = l + r >> 1;
            if(sufb[mid] >= X) {
                res = n - mid + 1;
                l = mid + 1;
            }
            else r = mid - 1;
        }
        if(res != -1) {
            ans = max(ans, X - (double)(n - i + 1) - res);
        }
        double Y = sufb[i];
        l = 1, r = n, res = -1;
        while(l <= r) {
            ll mid = l + r >> 1;
            if(sufa[mid] >= Y) {
                res = n - mid + 1;
                l = mid + 1;
            }
            else r = mid - 1;
        }
        if(res != -1) {
            ans = max(ans, Y - (double)(n - i + 1) - res);
        }
    }
    cout << setprecision(4) << fixed<< ans;
}

int main() {
    
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);

    #define NAME "hbmt"
    if(fopen(NAME".inp", "r")) {
        freopen(NAME".inp", "r", stdin);
        freopen(NAME".out", "w", stdout);
    }
    
    //int t;cin>>t;while(t--)
    hbmt();
    return 0;
}

Compilation message (stderr)

sure.cpp: In function 'int main()':
sure.cpp:70:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |         freopen(NAME".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
sure.cpp:71:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |         freopen(NAME".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 40 / 40
• Subtask 3: 40 / 40