Submission #867425

#	Time	Username	Problem	Language	Result	Execution time	Memory
867425		Cookie	Watching (JOI13_watching)	C++14	100 / 100	402 ms	64228 KiB

watching

#include<bits/stdc++.h>
#include<fstream>
using namespace std;
ifstream fin("nondec.in");
ofstream fout("nondec.out");
#define sz(a) (int)a.size()
#define ll long long
#define pb push_back
#define forr(i, a, b) for(int i = a; i < b; i++)
#define dorr(i, a, b) for(int i = a; i >= b; i--)
#define ld long double
#define vt vector
#include<fstream>
#define fi first
#define se second
#define pll pair<ll, ll>
#define pii pair<int, int>
const ld PI = 3.14159265359;
//using u128 = __uint128_t;
//const int x[4] = {1, -1, 0, 0};
//const int y[4] = {0, 0, 1, -1};
const ll mod = 1e9 + 7;
const int mxn = 2e5 + 5, mxq = 2e5 + 5, sq = 500, mxv = 1e7 + 5;
const ll inf = 1e9;
//const int base= (1 << 18);
int n, a, b;
ll x[mxn + 1];
pll dp[2005][2005];
void ckmin(pll &a, pll b){
    if(b.fi < a.fi)a = b;
    else if(a.fi == b.fi && b.se > a.se)a = b;
}
bool ck(ll mid){
    forr(i, 1, n + 1){
        forr(j, 0, a + 1){
            dp[i][j] = make_pair(inf, 0);
        }
    }
    dp[1][0] = make_pair(1, 2 * mid - 1);
    dp[1][1] = make_pair(0, mid - 1);
    for(int i = 1; i < n; i++){
        for(int j = 0; j <= a; j++){
            if(dp[i][j].first == inf)continue;
            if(dp[i][j].second >= x[i + 1] - x[i]){
                ckmin(dp[i + 1][j], make_pair(dp[i][j].first, dp[i][j].second - (x[i + 1] - x[i])));
            }if(j < a){
                ckmin(dp[i + 1][j + 1], make_pair(dp[i][j].first, mid - 1));
            }ckmin(dp[i + 1][j], make_pair(dp[i][j].first + 1, mid * 2 - 1));
        }
    }
    for(int i = 0; i <= a; i++){
        if(dp[n][i].first <= b)return(1);
    }
    return(0);
}
signed main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> n >> a >> b;
  if(a + b >= n){
	cout << 1;
    return(0);
  }
    for(int i = 1; i <= n; i++)cin >> x[i];
    sort(x + 1, x + n + 1);
    ll l = 1, r = 1e9, ans;
    while(l <= r){
        ll mid = (l + r) >> 1;
        if(ck(mid)){
            ans = mid; r = mid - 1;
        }else{
            l = mid + 1;
        }
    }
    cout << ans;
    return(0);
}

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