/* https://hsin.hr/ceoi/competition/ceoi2021_day2_editorial.pdf */
#include <stdio.h>
#define N 500000
#define N_ (1 << 19) /* N_ = pow2(ceil(log2(N))) */
#define INF 0x3f3f3f3f
int min(int a, int b) { return a < b ? a : b; }
unsigned int X = 12345;
int rand_() {
return (X *= 3) >> 1;
}
int tt[N], dd[N];
void sort(int *ii, int l, int r) {
while (l < r) {
int i = l, j = l, k = r, i_ = ii[l + rand_() % (r - l)], tmp;
while (j < k)
if (dd[ii[j]] == dd[i_])
j++;
else if (dd[ii[j]] < dd[i_]) {
tmp = ii[i], ii[i] = ii[j], ii[j] = tmp;
i++, j++;
} else {
k--;
tmp = ii[j], ii[j] = ii[k], ii[k] = tmp;
}
sort(ii, l, i);
l = k;
}
}
int sum[N_ * 2], pref[N_ * 2], ss[N_], kk[N_], n_;
void pul(int i) {
int l = i << 1, r = l | 1;
sum[i] = sum[l] + sum[r];
pref[i] = min(pref[l], sum[l] + pref[r]);
}
void build(int n) {
int i;
n_ = 1;
while (n_ < n)
n_ <<= 1;
for (i = 1; i < n; i++)
ss[i] = 1;
for (i = 0; i < n_; i++)
sum[n_ + i] = ss[i], pref[n_ + i] = kk[i] == 0 ? INF : ss[i];
for (i = n_ - 1; i > 0; i--)
pul(i);
}
void update(int i, int s, int k) {
ss[i] += s, kk[i] += k;
sum[n_ + i] = ss[i], pref[n_ + i] = kk[i] == 0 ? INF : ss[i];
i += n_;
while (i > 1)
pul(i >>= 1);
}
int main() {
static int aa[N], ii[N], ll[N], rr[N], pp[N];
int n, n_, i, j;
long long ans;
scanf("%d", &n);
for (i = 0; i < n; i++)
scanf("%d", &aa[i]);
for (i = 0; i < n; i++)
ll[i] = aa[i] == -1 ? i : (i == 0 ? -INF : ll[i - 1]);
for (i = n - 1; i >= 0; i--)
rr[i] = aa[i] == -1 ? i : (i + 1 == n ? INF : rr[i + 1]);
n_ = 0;
for (i = 0; i < n; i++)
if (aa[i] > 0) {
if (i - ll[i] <= rr[i] - i)
tt[i] = -1, dd[i] = i - ll[i];
else
tt[i] = 1, dd[i] = rr[i] - i;
ii[n_++] = i;
}
ans = 0;
for (i = 0; i < n; i++)
if (aa[i] > 0)
ans += aa[i];
for (j = 0; j < n; j++)
if (aa[j] == -1) {
i = j - 1;
while (i >= 0 && aa[i] == 0)
i--;
if (i >= 0 && aa[i] > 0)
pp[j] = i, kk[i]++, ans--;
else
pp[j] = -1;
}
sort(ii, 0, n_);
build(n);
for (i = 0; i < n_; i++) {
int i_ = ii[i], r = rr[i_], p;
while (kk[i_] <= aa[i_])
if (tt[i_] == -1) {
if (kk[i_] == aa[i_])
break;
if (kk[i_] == 0) {
update(i_, 0, 1);
if (i_ + 1 < n)
update(i_ + 1, -dd[i_] * 2, 0);
} else
update(i_, -dd[i_] * 2, 1);
if (pref[1] >= 0)
ans--;
else {
if (kk[i_] == 1) {
update(i_, 0, -1);
if (i_ + 1 < n)
update(i_ + 1, dd[i_] * 2, 0);
} else
update(i_, dd[i_] * 2, -1);
break;
}
} else {
p = r == INF ? INF : pp[r];
if (i_ != p)
break;
while (p >= 0 && kk[p] == aa[p])
p--;
if (p < 0 || aa[p] == -1)
break;
update(i_, -dd[i_] * 2, 1);
if (pref[1] >= 0)
pp[r] = p, ans--;
else {
update(i_, dd[i_] * 2, -1);
break;
}
}
}
printf("%lld\n", ans);
return 0;
}
Compilation message
tortoise.c: In function 'main':
tortoise.c:73:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
73 | scanf("%d", &n);
| ^~~~~~~~~~~~~~~
tortoise.c:75:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
75 | scanf("%d", &aa[i]);
| ^~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
0 ms |
284 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
0 ms |
284 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
0 ms |
284 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
0 ms |
284 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
0 ms |
284 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
