Submission #761663

#	Time	Username	Problem	Language	Result	Execution time	Memory
761663		hgmhc	도넛 (JOI14_ho_t3)	C++17	100 / 100	187 ms	2696 KiB

2014_ho_t3

#include <bits/stdc++.h>
#define rep(i,a,b) for (auto i = (a); i <= (b); ++i)
#define Mup(x,y) x = max(x,y)
#define mup(x,y) x = min(x,y)
#define all(x) begin(x),end(x)
#define per(i,a,b) for (auto i = (b); i >= (a); --i)
using namespace std;
using ll = long long;
using ii = pair<int,int>;
#define dbg(...) fprintf(stderr,__VA_ARGS__)

const int N = 1e5+3;
int n, a[2*N];
ll p[2*N], S;

bool valid(ll l) {
    int s = 1, e = 0;
    ll sum = 0;
    while (s <= n and e < n+s) {
        if (sum < l) {
            sum += a[++e];
        } else {
            int x = e+1, y = n+n, m;
            while (x <= y) {
                m = (x+y)/2;
                if (p[m]-p[e] >= sum) y = m-1;
                else x = m+1;
            }
            if (p[x]-p[e] > 0 and S-(p[x]-p[e])-sum >= sum) {
                // dbg("%lld: [%d,%d]\n", sum,s,e);
                // dbg("%lld: [%d,%d]\n", p[x]-p[e],e+1,x);
                // dbg("%lld: [%d,%d]\n", S-(p[x]-p[e])-sum,x+1,s-1);
                return true;
            }
            
            sum -= a[s++];
        }
    }
    return false;
}

int main() {
    scanf("%d", &n);
    rep(i,1,n) scanf("%d", &a[i]), p[i] = p[i-1]+a[i], a[i+n] = a[i];
    S = p[n];
    rep(i,n+1,n+n) p[i] = p[i-1]+a[i];
    ll x = 0, y = 1e15, m;
    while (x <= y) {
        m = (x+y)/2;
        if (valid(m)) x = m+1;
        else y = m-1;
    }
    printf("%lld", y);
}

Compilation message (stderr)

2014_ho_t3.cpp: In function 'int main()':
2014_ho_t3.cpp:43:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
2014_ho_t3.cpp:44:21: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |     rep(i,1,n) scanf("%d", &a[i]), p[i] = p[i-1]+a[i], a[i+n] = a[i];
      |                ~~~~~^~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 30 / 30
• Subtask 4: 50 / 50