#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#define mp make_pair
#define fi first
#define lb lower_bound
#define se second
#define endl "\n"
using namespace std;
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
// http://xorshift.di.unimi.it/splitmix64.c
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
int n, m;
cin >> n >> m;
int blk = 200;
vector<int> weights[n];
int init = -1, initp = -1, target = -1;
map<pair<int, int>, int> pti;
set<int> s[(int)1e5];
int t = 0;
for(int i = 1; i <= blk; ++i) {
for(int j = 0; j < i; ++j)
pti[mp(j, i)] = t++;
}
for(int i = 1; i <= m; ++i) {
int b, p;
cin >> b >> p;
if(i == 1)
init = b, initp = p;
else if(i == 2)
target = b;
// b -> pos
// p -> multiple
weights[b].push_back(p);
for(int j = 1; j <= blk; ++j) {
//cout << "INSERT " << b % j << " " << j << " " << b << endl;
s[pti[mp(b % j, j)]].insert(b);
}
}
// gaperlu cek semua cukup cek yg ada weights
// kalo udh proc weight jg gperlu
// kalo <= blk maka memo tiap pair int modulo dalam vector
// kalo > blk maka cek manual
// doge cmn boleh gerak dr ori node (gaboleh meet di tengah)
// hence cukup dijkstra dengan 1 origin, terus klo intersect lainnya bs langsung dijkstra aja
// tiap node ada theoretically n^2 dijkstra state yg mgkn?
// tp yg high modulo itu sparse, jadi bs simpan manual pakai sorted vector/semacamnya
priority_queue<pair<int, pair<int, pair<int, int>>>, vector<pair<int, pair<int, pair<int, int>>>>, greater<pair<int, pair<int, pair<int, int>>>>> pq;
// fi -> dist
// se.fi -> idx
// se.se.fi -> current p
// se.se.se -> tanda dr atas/bawah
// guna -> reduce double counting
//cout << init << " " << initp << endl;
pq.push(mp(0, mp(init, mp(initp, -1))));
int d[n + 1];
unordered_map<int, bool, custom_hash> vis[n];
memset(d, -1, sizeof(d));
// cek ada yg bs sampai ke target atau tidak, kalo tidak langsung output false
// kalo iya, maka ada pembuktian min path tidak sepanjang itu?
while(pq.size()) {
int dist = pq.top().fi, idx = pq.top().se.fi, curp = pq.top().se.se.fi, tanda = pq.top().se.se.se;
pq.pop();
//cout << dist << " " << idx << endl;
if(vis[idx][curp])
continue;
if(d[idx] == -1)
d[idx] = dist;
d[idx] = min(d[idx], dist);
for(auto i : weights[idx]) {
if(!vis[idx][i]) {
if(i > blk) {
int tmp = idx + i;
while(tmp < n && !weights[tmp].size())
tmp += i;
if(tmp < n && !vis[tmp][i])
pq.push(mp(dist + (tmp - idx) / i, mp(tmp, mp(i, 0))));
tmp = idx - i;
while(tmp >= 0 && !weights[tmp].size())
tmp -= i;
if(tmp >= 0 && !vis[tmp][i])
pq.push(mp(dist + (idx - tmp) / i, mp(tmp, mp(i, 1))));
}
else {
int mres = idx % i;
int x = pti[mp(mres, i)];
int nxtidx = -1, pridx = -1;
while(s[x].size() && s[x].lb(idx) != s[x].end()) {
int tmp = *s[x].lb(idx);
//cout << "FIND NXT " << tmp << " " << weights[tmp].size() << endl;
if(weights[tmp].size() && tmp != idx) {
nxtidx = tmp;
break;
}
s[x].erase(s[x].lb(idx));
}
while(s[x].size() && s[x].lb(idx) != s[x].begin()) {
int tmp = *--s[x].lb(idx);
if(weights[tmp].size() && tmp != idx) {
pridx = tmp;
break;
}
s[x].erase(--s[x].lb(idx));
}
//cout << nxtidx << " " <<pridx << endl;
if(nxtidx != -1 && !vis[nxtidx][i]) {
pq.push(mp(dist + (nxtidx - idx) / i, mp(nxtidx, mp(i, 0))));
}
if(pridx != -1 && !vis[pridx][i]) {
pq.push(mp(dist + (idx - pridx) / i, mp(pridx, mp(i, 1))));
}
}
}
vis[idx][i] = 1;
}
weights[idx].clear();
//cout << idx << " " << curp << endl;
if(!vis[idx][curp]) {
vis[idx][curp] = 1;
//cout << curp << " " << blk << endl;
if(curp > blk) {
int tmp = idx + curp;
if(tanda != 1) {
while(tmp < n && !weights[tmp].size())
tmp += curp;
if(tmp < n && !vis[tmp][curp])
pq.push(mp(dist + (tmp - idx) / curp, mp(tmp, mp(curp, 0))));
}
if(tanda != 0) {
tmp = idx - curp;
while(tmp >= 0 && !weights[tmp].size())
tmp -= curp;
if(tmp >= 0 && !vis[tmp][curp])
pq.push(mp(dist + (idx - tmp) / curp, mp(tmp, mp(curp, 1))));
}
}
else {
int mres = idx % curp;
int x = pti[mp(mres, curp)];
int nxtidx = -1, pridx = -1;
while(s[x].size() && s[x].lb(idx) != s[x].end()) {
int tmp = *s[x].lb(idx);
if(weights[tmp].size()) {
nxtidx = tmp;
break;
}
s[x].erase(s[x].lb(idx));
}
while(ss[x].size() && [x].lb(idx) != s[x].begin()) {
int tmp = *--s[x].lb(idx);
if(weights[tmp].size()) {
pridx = tmp;
break;
}
s[x].erase(--s[x].lb(idx));
}
//cout << nxtidx << " " << pridx << endl;
if(nxtidx != -1 && tanda != 1 && !vis[nxtidx][curp]) {
pq.push(mp(dist + (nxtidx - idx) / curp, mp(nxtidx, mp(curp, 0))));
}
if(pridx != -1 && tanda != 0 && !vis[pridx][curp]) {
pq.push(mp(dist + (idx - pridx) / curp, mp(pridx, mp(curp, 1))));
}
}
}
if(idx == target)
break;
}
cout << d[target] << endl;
}
Compilation message
skyscraper.cpp: In function 'int main()':
skyscraper.cpp:161:23: error: 'ss' was not declared in this scope; did you mean 's'?
161 | while(ss[x].size() && [x].lb(idx) != s[x].begin()) {
| ^~
| s
skyscraper.cpp: In lambda function:
skyscraper.cpp:161:42: error: expected '{' before '.' token
161 | while(ss[x].size() && [x].lb(idx) != s[x].begin()) {
| ^
skyscraper.cpp: In function 'int main()':
skyscraper.cpp:5:12: error: 'struct main()::<lambda()>' has no member named 'lower_bound'
5 | #define lb lower_bound
| ^~~~~~~~~~~
skyscraper.cpp:161:43: note: in expansion of macro 'lb'
161 | while(ss[x].size() && [x].lb(idx) != s[x].begin()) {
| ^~
