Submission #677687

#	Time	Username	Problem	Language	Result	Execution time	Memory
677687		mjhmjh1104	Seesaw (JOI22_seesaw)	C++17	0 / 100	1 ms	212 KiB

seesaw

#include <cstdio>
#include <numeric>
#include <algorithm>
using namespace std;

int n, a[200006];

double f() {
    long long sum = accumulate(a, a + n, 0LL);
    double init = sum / (double)n, curr = init;
    double mx = curr, mn = curr;
    int l = 0, r = n - 1, cnt = n;
    while (l < r) {
        if (curr < init) sum -= a[l++];
        else sum -= a[r--];
        cnt--;
        curr = sum / (double)cnt;
        mx = max(mx, curr);
        mn = min(mn, curr);
    }
    return mx - mn;
}

double g() {
    long long sum = accumulate(a, a + n, 0LL);
    double init = sum / (double)n, curr = init;
    double mx = curr, mn = curr;
    int l = 0, r = n - 1, cnt = n;
    while (l < r) {
        if (curr > init) sum -= a[r--];
        else sum -= a[l++];
        cnt--;
        curr = sum / (double)cnt;
        mx = max(mx, curr);
        mn = min(mn, curr);
    }
    return mx - mn;
}

double f2() {
    long long sum = accumulate(a, a + n, 0LL);
    double init = sum / (double)n, curr = init;
    double mx = curr, mn = curr;
    int l = 0, r = n - 1, cnt = n;
    while (l < r) {
        if (curr - a[r] >= init) sum -= a[r--];
        else sum -= a[l++];
        cnt--;
        curr = sum / (double)cnt;
        mx = max(mx, curr);
        mn = min(mn, curr);
    }
    return mx - mn;
}

double g2() {
    long long sum = accumulate(a, a + n, 0LL);
    double init = sum / (double)n, curr = init;
    double mx = curr, mn = curr;
    int l = 0, r = n - 1, cnt = n;
    while (l < r) {
        if (curr - a[l] <= init) sum -= a[l++];
        else sum -= a[r--];
        cnt--;
        curr = sum / (double)cnt;
        mx = max(mx, curr);
        mn = min(mn, curr);
    }
    return mx - mn;
}

int main() {
    scanf("%d", &n);
    for (int i = 0; i < n; i++) scanf("%d", a + i);
    printf("%.10f", min({ f(), g(), f2(), g2() }));
}

Compilation message (stderr)

seesaw.cpp: In function 'int main()':
seesaw.cpp:73:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
seesaw.cpp:74:38: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |     for (int i = 0; i < n; i++) scanf("%d", a + i);
      |                                 ~~~~~^~~~~~~~~~~~~

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