Submission #82058

#	Time	Username	Problem	Language	Result	Execution time	Memory
82058		wzy	Boxes with souvenirs (IOI15_boxes)	C++11	25 / 100	2 ms	380 KiB

boxes

#include <bits/stdc++.h>
#include "boxes.h"
using namespace std;
#define F first
#define S second
long long dpL[10000001] , dpR[10000001]; 

long long delivery(int N, int K, int L, int p[]) {
	#define int long long 
	int ans = (int) 1e18;
	int k = K;
	int n = N;
	int l = L;
	for(int i = 0 ; i < N ;i ++){
		dpL[i] = 2*p[i];
		if(i >= K) dpL[i] = dpL[i-k] + 2*p[i]; // pick the last block and then solve for [0 , i-k]
	}
	for(int j = N - 1 ; j >= 0 ; j--){
		int u = j + K ;
		dpR[j] = 2*(L - p[j]);
		if(u <= n - 1) dpR[j] = dpR[u] + 2*(L - p[j]); 
	}
	#define pii pair<long long, long long> 
	deque<pii> dq;
	int left = 1;
	for(int i = 0 ; i < N  - 1; i ++){
		while(dq.size() && dq.front().second <= i) dq.pop_front();
		left = max(left, i + 1);
		while(left < N && k >= (left - i - 1)){
			while(dq.size() && dq.back().first >= dpR[left]) dq.pop_back();
			dq.push_back(pii(dpR[left] , left));
			left++;
		}
		ans = min(ans , dpL[i] + dpR[i+1]);
		ans = min(ans , dpL[i] + dq.front().F + L);
	}
	for(int i = 0 ; i < N ; i ++){
		int X = (i+1);
		X = n  - X;
		if(X <= k){
			ans = min(ans , dpL[i] + L);
		}
		int Y = N - i ;
		Y = N - Y;
		if(Y <= k) ans = min(ans , dpR[i] + L);
	}
	ans = min(ans , dpL[N - 1]);
	ans = min(ans , dpR[0]);
    return ans;
}

Compilation message (stderr)

boxes.cpp: In function 'long long int delivery(int, int, int, int*)':
boxes.cpp:13:6: warning: unused variable 'l' [-Wunused-variable]
  int l = L;
      ^

• Subtask 1: 10 / 10
• Subtask 2: 0 / 10
• Subtask 3: 15 / 15
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30