Submission #40513

#	Time	Username	Problem	Language	Result	Execution time	Memory
40513		mohammad_kilani	Split the sequence (APIO14_sequence)	C++14	0 / 100	1 ms	488 KiB

sequence

#include <bits/stdc++.h>
using namespace std;
#define mod 1000000007
#define oo 1000000000
const double PI = acos(-1);
const int N = 100010 , K = 201;
int arr[N] , n , k , a, low , high , res , mid , best[N][K];
long long dp[N][K] , sum[N] , cur , cur2 ; 
set < pair<int,int> > st;
set < pair<int,int> > :: iterator it ;

int main(){
	scanf("%d%d",&n,&k);
	for(int i=0;i<n;i++){
		scanf("%d",&arr[i]);
		sum[i+1] = sum[i] + arr[i];
	}
	for(int i=0;i<n;i++)
		for(int j=0;j<k;j++)
			dp[i][j] = -1e17;
	for(int j=k-1;j>=0;j--){
		st.clear();
		st.insert(make_pair(n-1,n-1));
		for(int i=n-2;i>=0;i--){
				it = st.lower_bound(make_pair(i,0));
				a = it->second;
				dp[i][j] = dp[a][j+1] + (sum[a] - sum[i]) * (sum[n] - sum[a]);
				best[i][j] = a;
				low = 0 , high = i - 1 , res = -1;
				while(high >= low){
					mid = (low + high) / 2;
					it = st.lower_bound(make_pair(mid,0));
					assert(it != st.end());
					a = it->second;
					cur = dp[a][j+1] + (sum[a] - sum[mid]) * (sum[n] - sum[a]);
					cur2 = dp[i][j+1] + (sum[i] - sum[mid]) * (sum[n] - sum[i]);
					if(cur > cur2){
						high = mid - 1;
					}
					else{
						res = mid;
						low = mid + 1;
					}
				}
				it = st.lower_bound(make_pair(0,0));
				while(it != st.end() && it->first <= res){
					st.erase(it);
					it = st.lower_bound(make_pair(0,0));
				}
				if(res != -1) st.insert(make_pair(res,i));
		}
	}
	cout << dp[0][0] << endl;
	int idx = 0;
 	for(int i=0;i<k;i++){
 		if(i > 0) putchar(' ');
 		printf("%d",best[idx][i]);
 		idx = best[idx][i];
 	}
 	puts("");
 	return 0;
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:13:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&k);
                     ^
sequence.cpp:15:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&arr[i]);
                      ^

• Subtask 1: 0 / 11
• Subtask 2: 0 / 11
• Subtask 3: 0 / 11
• Subtask 4: 0 / 17
• Subtask 5: 0 / 21
• Subtask 6: 0 / 29