제출 #846918

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
846918		BamshooT	Feast (NOI19_feast)	C++14	22 / 100	77 ms	13392 KiB

feast

#include <iostream>
#include <algorithm>
#include <vector>
#include <math.h>
#include <cstdlib>
 
#define ll long long
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define inf -1e18
#define fi first
#define se second
 
using namespace std;
 
typedef pair <ll, int> li;
 
const int N = 3e5 + 9, M = 2e3 + 9;
int n, k;
ll a[N], pre[N], dp[M][M];
 
void sub1(){
 
    for (int i = 1; i <= k; ++i){
        ll cur = 0;
        for (int j = 1; j <= n; ++j) {
            cur = max(cur, dp[i-1][j] - pre[j]);
            dp[i][j] = max(dp[i][j-1], cur + pre[j]);
        }
    }
    cout << dp[k][n];
}
 
pair<ll, int> f[N];
 
void maximize(li &a, li b){
    if (a.fi < b.fi) a = b;
    if (a.fi == b.fi && a.se > b.se) a = b;
}
 
li calc(ll cost){
    li best = {0, 0};
    for (int i = 1; i <= n; ++i) {
        f[i] = f[i-1];
        maximize(f[i], {pre[i] + best.fi - cost , best.se + 1});
        maximize(best, {f[i].fi - pre[i], f[i].se});
    }
    //f[n].se *= -1;
    return f[n];
}
 
void sub2(){
    ll lo = -1e14, hi = 1e14, ans = 0;
    while (lo < hi) {
        ll mid = lo + hi >> 1;
        li tmp = calc(mid);
        if (tmp.se <= k) {
            hi = mid;
        } else lo = mid + 1;
    }
    li tmp = calc(lo);
    cout << tmp.fi + k*lo;
}
 
int main(){
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
   // freopen("nhap.inp", "r", stdin);
  //  freopen("xuat.out", "w", stdout);
    cin >> n >> k;
    FOR(i, 1, n) {
        cin >> a[i];
        pre[i] = pre[i-1] + a[i];
    }
   // if (max(k, n) <= 2000) sub1(); else
    sub2();
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

feast.cpp: In function 'void sub2()':
feast.cpp:54:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   54 |         ll mid = lo + hi >> 1;
      |                  ~~~^~~~
feast.cpp:52:31: warning: unused variable 'ans' [-Wunused-variable]
   52 |     ll lo = -1e14, hi = 1e14, ans = 0;
      |                               ^~~

• Subtask 1: 4 / 4
• Subtask 2: 0 / 8
• Subtask 3: 18 / 18
• Subtask 4: 0 / 10
• Subtask 5: 0 / 11
• Subtask 6: 0 / 20
• Subtask 7: 0 / 29