제출 #56548

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
56548		luciocf	구경하기 (JOI13_watching)	C++14	100 / 100	336 ms	16636 KiB

watching

#include <bits/stdc++.h>

using namespace std;

const int MAXN = 2010;

typedef long long ll;

int n, p, q, num[MAXN], dp[MAXN][MAXN], next_[2][MAXN];

int busca2(int k)
{
    if (k > num[n]) return n;

    int ini = 1, fim = n, ans;
    while (ini <= fim)
    {
        int mid = (ini+fim)>>1;

        if (num[mid] <= k) ans = mid, ini = mid+1;
        else fim = mid-1;
    }
    return ans;
}

bool ok(int w)
{
    memset(dp, 0, sizeof dp);
    for (int i = 1; i <= p; i++)
        for (int j = 1; j <= q; j++)
            dp[i][j] = 1;

    for (int i = 1; i <= n; i++)
        next_[0][i] = busca2(num[i]+w-1), next_[1][i] = busca2(num[i]+2*w-1);

    for (int i = 0; i <= p; i++)
    {
        for (int j = 0; j <= q; j++)
        {
            if (i)
                dp[i][j] = max(dp[i][j], next_[0][min(n, dp[i-1][j]+1)]);
            if (j)
                dp[i][j] = max(dp[i][j], next_[1][min(n, dp[i][j-1]+1)]);
        }
    }
    return (dp[p][q] >= n);
}

int busca(void)
{
    int ini = 1, fim = 1e9+10, ans;
    while (ini <= fim)
    {
        int mid = (ini+fim)>>1;

        if (ok(mid)) ans = mid, fim = mid-1;
        else ini = mid+1;
    }
    return ans;
}

int main(void)
{
    scanf("%d %d %d", &n, &p, &q);

    for (int i = 1; i <= n; i++) scanf("%d", &num[i]);

    if (p+q >= n)
    {
        cout << "1\n";
        return 0;
    }

    sort(num+1, num+n+1);
    printf("%d\n", busca());
}

컴파일 시 표준 에러 (stderr) 메시지

watching.cpp: In function 'int main()':
watching.cpp:64:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d", &n, &p, &q);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:66:39: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for (int i = 1; i <= n; i++) scanf("%d", &num[i]);
                                  ~~~~~^~~~~~~~~~~~~~~
watching.cpp: In function 'int busca2(int)':
watching.cpp:15:27: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
     int ini = 1, fim = n, ans;
                           ^~~
watching.cpp: In function 'bool ok(int)':
watching.cpp:34:55: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
         next_[0][i] = busca2(num[i]+w-1), next_[1][i] = busca2(num[i]+2*w-1);
                                           ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
watching.cpp:34:21: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
         next_[0][i] = busca2(num[i]+w-1), next_[1][i] = busca2(num[i]+2*w-1);
         ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
watching.cpp: In function 'int busca()':
watching.cpp:59:12: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
     return ans;
            ^~~

• Subtask 1: 50 / 50
• Subtask 2: 50 / 50