Submission #888967

#	Time	Username	Problem	Language	Result	Execution time	Memory
888967		dwuy	Watching (JOI13_watching)	C++14	100 / 100	211 ms	32084 KiB

watching

/// dwuy: _,\,,,_\,__,\,,_
#include <bits/stdc++.h>

#define fastIO ios_base::sync_with_stdio(false); cin.tie(NULL)
#define file(a) freopen(a".inp","r",stdin); freopen(a".out", "w",stdout)
#define fi first
#define se second
#define endl "\n"
#define len(s) int32_t(s.length())
#define MASK(k)(1LL<<(k))
#define TASK ""
#define int long long

using namespace std;

typedef tuple<int, int, int> tpiii;
typedef pair<double, double> pdd;
typedef pair<int, int> pii;
typedef long long ll;

const long long OO = 1e18;
const int MOD = 1e9 + 7;
const int INF = 1e9;
const int MX = 2005;

int n, p, q;
int a[MX];
int dp[MX][MX];
/// dp[i][j] : least large camera to check a[1, i], used j small camera;

void nhap(){
    cin >> n >> p >> q;
    for(int i=1; i<=n; i++) cin >> a[i];
    if(p+q>=n){
        cout << 1;
        exit(0);
    }
    sort(a+1, a+1+n);
}

bool ok(int mid){
    memset(dp, 0x3f, sizeof dp);
    memset(dp[0], 0, sizeof dp[0]);
    for(int i=1, sm=1, bg=1; i<=n; i++){
        while(a[i] - a[sm] + 1 > mid) sm++;
        while(a[i] - a[bg] + 1 > mid+mid) bg++;
        for(int j=0; j<=p; j++){
            dp[i][j] = min({dp[i][j], (j? dp[sm-1][j-1] : INF), dp[bg-1][j] + 1});
        }
    }
    return dp[n][p] <= q;
}

void solve(){
    int res = 0;
    for(int lo=1, hi=1000000000; lo<=hi;){
        int mid = (lo+hi)>>1;
        if(ok(mid)) res = mid, hi = mid - 1;
        else lo = mid + 1;
    }
    cout << res;
}

int32_t main(){
    fastIO;
    //file(TASK);

    nhap();
    solve();

    return 0;
}

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