#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mod 1000000007
#define h1 7897897897897897
#define h2 7897466719774591
#define b1 98762051
#define b2 98765431
#define inf 1000000000
#define pi 3.1415926535897932384626
#define LMAX 9223372036854775807
#define ll long long
#define fi first
#define se second
#define pii pair<int, int>
#define pll pair<ll, ll>
#define vi vector<int>
#define vl vector<ll>
#define vp vector<pii>
#define SET(a, b) memset(a, b, sizeof(a));
#define all(x) (x).begin(), (x).end()
#define flush fflush(stdout)
#define debug printf("Hello\n")
#define FOR(i, a, b) for (int i = (a); i <= (b); i++)
#define FORD(i, a, b) for (int i = (a); i >= (b); i--)
int n, m, k, x, y, sum, cnt, ans = inf, b[30005], po[30005];
int d[30005][175];
vi v[30005];
const int SQ = 173;
struct state {
int dist, pos, power; //for buildings: power = 0
bool operator <(const state& rhs) const {
return dist > rhs.dist;
}
};
vector <pii> edges[30005][175]; //(position, power)
int main () {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
scanf("%d %d", &n, &m);
FOR(i, 1, m) {
scanf("%d %d", &b[i], &po[i]);
v[b[i]].pb(po[i]);
}
FOR(i, 0, n-1) {
sort(all(v[i]));
auto it = unique(v[i].begin(), v[i].end());
v[i].resize(distance(v[i].begin(), it));
FOR(j, 0, 174) {
d[i][j] = inf;
}
}
d[0][0] = 0;
priority_queue <state> pq;
pq.push((state){0, 0, 0});
while (!pq.empty()) {
state cur = pq.top();
pq.pop();
if (d[cur.pos][cur.power] != cur.dist) continue;
if (cur.pos == 1) {
ans = min(ans, cur.dist);
continue;
}
if (cur.power == 0) {
for (auto p: v[cur.pos]) {
if (p >= SQ) {
for (int j = cur.pos - p, cost = 1; j >= 0; j -= p, cost++) {
if (cur.dist + cost < d[j][0]) {
d[j][0] = cur.dist + cost;
pq.push((state){d[j][0], j, 0});
}
}
for (int j = cur.pos + p, cost = 1; j < n; j += p, cost++) {
if (cur.dist + cost < d[j][0]) {
d[j][0] = cur.dist + cost;
pq.push((state){d[j][0], j, 0});
}
}
} else {
if (cur.dist < d[cur.pos][p]) {
d[cur.pos][p] = cur.dist;
pq.push((state){d[cur.pos][p], cur.pos, p});
}
}
}
} else {
if (cur.dist < d[cur.pos][0]) {
d[cur.pos][0] = cur.dist;
pq.push((state){d[cur.pos][0], cur.pos, 0});
}
if (cur.pos + cur.power < n && cur.dist + 1 < d[cur.pos + cur.power][cur.power]) {
d[cur.pos + cur.power][cur.power] = cur.dist + 1;
pq.push((state){d[cur.pos + cur.power][cur.power], cur.pos + cur.power, cur.power});
}
if (cur.pos - cur.power >= 0 && cur.dist + 1 < d[cur.pos - cur.power][cur.power]) {
d[cur.pos - cur.power][cur.power] = cur.dist + 1;
pq.push((state){d[cur.pos - cur.power][cur.power], cur.pos - cur.power, cur.power});
}
}
}
if (ans == inf) printf("-1\n");
else printf("%d\n", ans);
return 0;
}
Compilation message
skyscraper.cpp: In function 'int main()':
skyscraper.cpp:41:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d %d", &n, &m);
~~~~~^~~~~~~~~~~~~~~~~
skyscraper.cpp:43:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d %d", &b[i], &po[i]);
~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
117 ms |
124408 KB |
Output is correct |
2 |
Incorrect |
79 ms |
124424 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
85 ms |
124408 KB |
Output is correct |
2 |
Incorrect |
87 ms |
124408 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
79 ms |
124408 KB |
Output is correct |
2 |
Incorrect |
77 ms |
124408 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
92 ms |
124408 KB |
Output is correct |
2 |
Incorrect |
93 ms |
124408 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
91 ms |
124408 KB |
Output is correct |
2 |
Incorrect |
80 ms |
124408 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |