Submission #486149

#	Time	Username	Problem	Language	Result	Execution time	Memory
486149		Jomnoi	Rice Hub (IOI11_ricehub)	C++17	68 / 100	160 ms	632 KiB

ricehub

#include <bits/stdc++.h>
#include <ricehub.h>
#define DEBUG 0
using namespace std;

int cost(int R, int X[], int mid, long long B) {
    long long closest = 1e18, sum = 0;
    int l, r, pos, ct = 0, ok;
    for(int i = 0; i < R; i++) {
        if(abs(X[i] - mid) < closest) {
            closest = abs(X[i] - mid);
            pos = i;
        }
    }
    if(X[pos] <= mid) {
        r = min(R - 1, pos + 1);
        l = r - 1;
    }
    else {
        l = max(0, pos - 1);
        r = l + 1;
    }
    l = r - 1;
    while(1) {
        closest = 1e18;
        if(l >= 0 && closest > abs(mid - X[l])) {
            closest = abs(mid - X[l]);
            ok = 0;
        }
        if(r < R && closest > abs(X[r] - mid)) {
            closest = abs(X[r] - mid);
            ok = 1;
        }
        if(sum + closest > B) {
            return ct;
        }
        ct++;
        sum += closest;
        if(!ok) {
            l--;
        }
        else {
            r++;
        }
    }
    return R;
}

int besthub(int R, int L, int X[], long long B) {
    int l = 1, r = L, ans = 0, mid, cost1;
    int l2, r2, mid2, pos2, cost2;
    while(l <= r) {
        mid = (l + r) / 2;
        cost1 = cost(R, X, mid, B);
        l2 = l + 1, r2 = r, pos2 = r;
        while(l2 <= r2) {
            mid2 = (l2 + r2) / 2;
            if(cost1 == cost(R, X, mid2, B)) {
                l2 = mid2 + 1;
            }
            else {
                r2 = mid2 - 1;
                pos2 = min(pos2, mid2);
            }
        }
        cost2 = cost(R, X, pos2, B);
        if(cost1 > cost2) {
            r = mid - 1;
            ans = max(ans, cost1);
        }
        else {
            l = mid + 1;
            ans = max(ans, cost2);
        }
    }
    return ans;
}

Compilation message (stderr)

ricehub.cpp: In function 'int cost(int, int*, int, long long int)':
ricehub.cpp:39:9: warning: 'ok' may be used uninitialized in this function [-Wmaybe-uninitialized]
   39 |         if(!ok) {
      |         ^~
ricehub.cpp:20:24: warning: 'pos' may be used uninitialized in this function [-Wmaybe-uninitialized]
   20 |         l = max(0, pos - 1);
      |                    ~~~~^~~

• Subtask 1: 17 / 17
• Subtask 2: 25 / 25
• Subtask 3: 26 / 26
• Subtask 4: 0 / 32