Submission #1313372

#	Time	Username	Problem	Language	Result	Execution time	Memory
1313372		lev	Safety (NOI18_safety)	C++20	49 / 100	214 ms	196596 KiB

safety

#include <bits/stdc++.h>
#define int long long
#define fi first
#define se second
#define pii pair<int, int>
#define all(a) a.begin(), a.end()
using namespace std;

#ifdef LOCAL
#include "C:\Users\Dell\Downloads\template\template\icpc-notebook\Utilities\debug.h"
#else
#define debug(...) 42
#endif

const int mn = 5e5 + 5, N = 5e3 + 5, mod = 1e9 + 7, inf = 2e18;

int n, h, a[mn], dp[N][N];

namespace sub12567{
	bool check(){
		int r = 0;
		for(int i = 1; i <= n; i++){
			r = max(r, a[i]);
		}
		return (r <= 5000 && n <= 5000);
	}

	void sol(){
		fill(&dp[0][0], &dp[0][0] + N * N, inf);
		for(int i = 0; i <= 5000; i++) dp[0][i] = 0;

	    for(int i = 1; i <= n; i++){
	    	deque <int> dq;

	    	for(int j = 0; j < min(5000ll, h); j ++){
	    		while(!dq.empty() && dp[i - 1][dq.back()] > dp[i - 1][j]) dq.pop_back();
	    		dq.push_back(j);
	    	}

	    	for(int j = 0; j <= 5000; j++){
	    		while(!dq.empty() && dq.front() < max(0ll, j - h)) dq.pop_front();
	    		while(j + h <= 5000 && !dq.empty() && dp[i - 1][dq.back()] > dp[i - 1][j + h]) dq.pop_back();
	    		if(j + h <= 5000) dq.push_back(j + h);
	    		dp[i][j] = dp[i - 1][dq.front()] + abs(a[i] - j);
	    		// if(j <= 10){
	    		// 	debug(i, j, dp[i][j], dp[i - 1][dq.front()], abs(a[i] - j));
	    		// 	debug(dq);
	    		// }
	    	}
	    }

	    int res = inf;
	    for(int i = 0; i <= 5000; i ++) res = min(res, dp[n][i]);
	    cout << res << '\n';
	}
};

namespace sub3{
	bool check(){
		return (h == 0);
	}

	void sol(){
		sort(a + 1, a + n + 1);
		int res = 0;
		for(int i = 1; i <= n; i++){
			res += abs(a[i] - a[(n + 1) >> 1]);
		} 
		cout << res << '\n';
	}
};

namespace sub4{
	bool check(){
		return (n <= 10 && h <= 2);
	}

	int res = inf;

	void backtrack(int id, int cur, int val){
		if(id == n){
			res = min(res, val);
			return;
		}

		for(int i = - h; i <= h; i++){
			backtrack(id + 1, cur + i, val + abs(cur + i - a[id + 1]));
		}
	}

	void sol(){
		for(int id = 1; id <= n; id ++){
			for(int i = - h; i <= h; i++){
				backtrack(1, a[id] + i, abs(a[id] + i - a[1]));
			}
		}
		cout << res << '\n';
	}
};

void solve() {
    cin >> n >> h;
    for(int i = 1; i <= n; i++) cin >> a[i];
	if(sub4::check()) sub4::sol();
    else if(sub12567::check()) sub12567::sol();
	else if(sub3::check()) sub3::sol();
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    #define task "Kawabata"
    if (fopen(task".INP", "r")) {
        freopen(task".INP", "r", stdin);
        freopen(task".OUT", "w", stdout);
    }
    int t = 1;
    // cin >> t;
    while (t--) solve();
    return 0;
}
// Don't wanna lose anymore T_T
// Never let me go - Kazuo Ishiguro

Compilation message (stderr)

safety.cpp: In function 'int main()':
safety.cpp:114:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  114 |         freopen(task".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
safety.cpp:115:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  115 |         freopen(task".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 3 / 3
• Subtask 2: 4 / 4
• Subtask 3: 9 / 9
• Subtask 4: 5 / 5
• Subtask 5: 6 / 6
• Subtask 6: 11 / 11
• Subtask 7: 11 / 11
• Subtask 8: 0 / 22
• Subtask 9: 0 / 29