#include <stdio.h>
#include <string.h>
#define N 5000
#define INF 0x3f3f3f3f3f3f3f3fLL
int abs_(int a) { return a > 0 ? a : -a; }
int contains(int a, int b, int c) {
int tmp;
if (a > b)
tmp = a, a = b, b = tmp;
return a <= c && c <= b;
}
long long dd[N * N]; int iq[N * N + 1], pq[N * N], cnt;
int lt(int i, int j) { return dd[i] < dd[j]; }
int p2(int p) {
return (p *= 2) > cnt ? 0 : (p < cnt && lt(iq[p + 1], iq[p]) ? p + 1 : p);
}
void pq_up(int i) {
int p, q, j;
for (p = pq[i]; (q = p / 2) && lt(i, j = iq[q]); p = q)
iq[pq[j] = p] = j;
iq[pq[i] = p] = i;
}
void pq_dn(int i) {
int p, q, j;
for (p = pq[i]; (q = p2(p)) && lt(j = iq[q], i); p = q)
iq[pq[j] = p] = j;
iq[pq[i] = p] = i;
}
void pq_add_last(int i) {
iq[pq[i] = ++cnt] = i;
}
int pq_remove_first() {
int i = iq[1], j = iq[cnt--];
if (j != i)
pq[j] = 1, pq_dn(j);
pq[i] = 0;
return i;
}
int main() {
static int aa[N];
int n, i, j, u, v;
long long d;
scanf("%d", &n);
for (i = 0; i < n; i++)
scanf("%d", &aa[i]);
memset(dd, 0x3f, n * n * sizeof *dd);
dd[0 * n + (n - 2)] = 0, pq_add_last(0 * n + (n - 2));
while (cnt) {
u = pq_remove_first(), i = u / n, j = u % n;
if (i == j || i == j + 1) {
printf("%lld\n", dd[u]);
return 0;
}
if (i > 0) {
if (contains(aa[j], aa[j + 1], aa[i - 1])) {
v = (i - 1) * n + j, d = dd[u] + abs_(aa[i - 1] - aa[i]);
if (dd[v] > d) {
if (dd[v] == INF)
pq_add_last(v);
dd[v] = d, pq_up(v);
}
}
if (contains(aa[i], aa[i - 1], aa[j])) {
v = j * n + (i - 1), d = dd[u] + abs_(aa[j] - aa[i]);
if (dd[v] > d) {
if (dd[v] == INF)
pq_add_last(v);
dd[v] = d, pq_up(v);
}
}
if (contains(aa[i], aa[i - 1], aa[j + 1])) {
v = (j + 1) * n + (i - 1), d = dd[u] + abs_(aa[j + 1] - aa[i]);
if (dd[v] > d) {
if (dd[v] == INF)
pq_add_last(v);
dd[v] = d, pq_up(v);
}
}
}
if (i + 1 < n) {
if (contains(aa[j], aa[j + 1], aa[i + 1])) {
v = (i + 1) * n + j, d = dd[u] + abs_(aa[i + 1] - aa[i]);
if (dd[v] > d) {
if (dd[v] == INF)
pq_add_last(v);
dd[v] = d, pq_up(v);
}
}
if (contains(aa[i], aa[i + 1], aa[j])) {
v = j * n + i, d = dd[u] + abs_(aa[j] - aa[i]);
if (dd[v] > d) {
if (dd[v] == INF)
pq_add_last(v);
dd[v] = d, pq_up(v);
}
}
if (contains(aa[i], aa[i + 1], aa[j + 1])) {
v = (j + 1) * n + i, d = dd[u] + abs_(aa[j + 1] - aa[i]);
if (dd[v] > d) {
if (dd[v] == INF)
pq_add_last(v);
dd[v] = d, pq_up(v);
}
}
}
}
printf("NO\n");
return 0;
}
Compilation message
climbers.c: In function 'main':
climbers.c:59:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
59 | scanf("%d", &n);
| ^~~~~~~~~~~~~~~
climbers.c:61:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
61 | scanf("%d", &aa[i]);
| ^~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
340 KB |
Output is correct |
| 2 |
Correct |
1 ms |
1364 KB |
Output is correct |
| 3 |
Correct |
7 ms |
11988 KB |
Output is correct |
| 4 |
Correct |
41 ms |
92232 KB |
Output is correct |
| 5 |
Correct |
109 ms |
254796 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
212 KB |
Output is correct |
| 2 |
Correct |
0 ms |
340 KB |
Output is correct |
| 3 |
Correct |
0 ms |
468 KB |
Output is correct |
| 4 |
Correct |
1 ms |
340 KB |
Output is correct |
| 5 |
Correct |
1 ms |
2132 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
340 KB |
Output is correct |
| 2 |
Correct |
1 ms |
1364 KB |
Output is correct |
| 3 |
Correct |
70 ms |
12032 KB |
Output is correct |
| 4 |
Correct |
137 ms |
89620 KB |
Output is correct |
| 5 |
Correct |
165 ms |
92328 KB |
Output is correct |
| 6 |
Correct |
172 ms |
156012 KB |
Output is correct |
| 7 |
Correct |
190 ms |
151608 KB |
Output is correct |
| 8 |
Correct |
188 ms |
251852 KB |
Output is correct |
| 9 |
Correct |
214 ms |
240624 KB |
Output is correct |
| 10 |
Correct |
235 ms |
240708 KB |
Output is correct |
