Submission #30489

#	Time	Username	Problem	Language	Result	Execution time	Memory
30489		sampriti	Hacker (BOI15_hac)	C++14	100 / 100	766 ms	18784 KiB

hac

#include <cstdio>
#include <algorithm>
#include <set>

using namespace std;

int N;
int A[500000];
int P[500000];
int sum[500000];  // sum[i..(i+len)]
multiset<int> S;

int query(int i, int j) {
  if(i > j) {
    return query(i, N - 1) + query(0, j);
  }

  if(i == 0) return P[j];
  return P[j] - P[i - 1];
}

int main() {
  scanf("%d", &N);

  for(int i = 0; i < N; i++) scanf("%d", &A[i]);
  P[0] = A[0];
  for(int i = 1; i < N; i++) P[i] = P[i - 1] + A[i];

  int len = (N + 1)/2;
  for(int i = 0; i < N; i++) {
    sum[i] = query(i, (i + len - 1) % N);
  }

  int ans = 0;

  int L = 0 - (len - 1) + N, R = 0;
  int j = L;
  while(j != 1) {
    S.insert(sum[j]);
    j = (j + 1) % N;
  }

  for(int i = 0; i < N; i++) {
    ans = max(ans, *S.begin());
    S.erase(S.find(sum[L]));
    L = (L + 1) % N;
    R = (R + 1) % N;
    S.insert(sum[R]);
  }

  printf("%d\n", ans);
}

Compilation message (stderr)

hac.cpp: In function 'int main()':
hac.cpp:23:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &N);
                  ^
hac.cpp:25:48: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   for(int i = 0; i < N; i++) scanf("%d", &A[i]);
                                                ^

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 40 / 40