Aquarium

input/code.cpp: In function 'int main()':
input/code.cpp:50:20: warning: statement has no effect [-Wunused-value]
   50 | #define debug(...) 42
      |                    ^~
input/code.cpp:75:9: note: in expansion of macro 'debug'
   75 |         debug(v, cur, tot);
      |         ^~~~~
input/code.cpp:50:20: warning: statement has no effect [-Wunused-value]
   50 | #define debug(...) 42
      |                    ^~
input/code.cpp:82:9: note: in expansion of macro 'debug'
   82 |         debug(le, ri);
      |         ^~~~~

#include <bits/stdc++.h>
using namespace std;
#define int long long

string to_string(string s) {
    return '"' + s + '"';
}
 
string to_string(const char* s) {
    return to_string((string) s);
}
 
string to_string(bool b) {
    return (b ? "true" : "false");
}
 
template <typename A, typename B>
string to_string(pair<A, B> p) {
    return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
 
template <typename A>
string to_string(A v) {
    bool first = true;
    string res = "{";
    for (const auto &x : v) {
        if (!first) {
            res += ", ";
        }
        first = false;
        res += to_string(x);
    }
    res += "}";
    return res;
}
 
void debug_out() {
    cerr << endl;
}
 
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << " " << to_string(H);
    debug_out(T...);
}
 
#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

const int N = 10005;

int n, h[N], q, v;

signed main() {
    cin.tie(0)->sync_with_stdio(0);

    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> h[i];
    }
    cin >> q >> v;

    if (v <= h[q]) {
        cout << v << '\n';
        return 0;
    }

    v -= h[q];
    int le = q, ri = q, cur = h[q], tot = h[q];
    double add = 0;
    while (v) {
        debug(v, cur, tot);

        // find first column higher than cur to the left
        while (le >= 1 && h[le] <= cur) le--;
        // find first column higher than cur to the right
        while (ri <= n && h[ri] <= cur) ri++;

        debug(le, ri);

        // spill to left or right
        if (le < 1 || ri > n) break;

        if (h[le] < h[ri]) {
            // fill till h[le]
            int need = ((ri - le + 1) - 1) * h[le] - tot;
            if (v < need) {
                // does it fill until h[le]?
                if (v >= need - h[le]) {
                    cur = h[le];
                } else {
                    // doesn't
                    int left = v - (((ri - le + 1) - 2) * cur - tot);
                    add = (double)left / (double)((ri - le + 1) - 2);
                }
                break;
            }

            v -= need;
            tot += need;
            cur = h[le];
            continue;
        } else if (h[le] > h[ri]) {
            // fill till h[ri]
            int need = ((ri - le + 1) - 1) * h[ri] - tot;
            if (v < need) {
                // does it fill until h[le]?
                if (v >= need - h[ri]) {
                    cur = h[ri];
                } else {
                    // doesn't
                    int left = v - (((ri - le + 1) - 2) * cur - tot);
                    add = (double)left / (double)((ri - le + 1) - 2);
                }
                break;
            }

            v -= need;
            tot += need;
            cur = h[ri];
            continue;
        } else { // h[le] = h[ri]
            // fill till both
            int need = ((ri - le + 1) - 0) * h[ri] - tot;
            if (v < need) {
                // does it fill until both h[le] and h[ri]?
                if (v >= need - h[ri] - h[le]) {
                    cur = h[ri];
                } else {
                    // doesn't
                    int left = v - (((ri - le + 1) - 2) * cur - tot);
                    add = (double)left / (double)((ri - le + 1) - 2);
                }
                break;
            }

            v -= need;
            tot += need;
            cur = h[ri];
            continue;
        }
    }

    double final = cur + add;
    cout << fixed << setprecision(3) << final;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

Test 29

Verdict: ACCEPTED

Test 30

Verdict: ACCEPTED

Test 31

Verdict: ACCEPTED

Test 32

Verdict: ACCEPTED

Test 33

Verdict: ACCEPTED

Test 34

Verdict: ACCEPTED

Test 35

Verdict: ACCEPTED

Test 36

Verdict: ACCEPTED

Test 37

Verdict: ACCEPTED

Test 38

Verdict: ACCEPTED

Test 39

Verdict: ACCEPTED

Test 40

Verdict: ACCEPTED

Test 41

Verdict: ACCEPTED

Test 42

Verdict: ACCEPTED

Test 43

Verdict: ACCEPTED

Test 44

Verdict: ACCEPTED