Submission #486596

# Submission time Handle Problem Language Result Execution time Memory
486596 2021-11-12T05:32:38 Z socho Robot (JOI21_ho_t4) C++14
100 / 100
1672 ms 104776 KB
/*
	Implementation of Aruj's idea of splitting cases into "forcibly recolour others" and "anything is ok"
*/
#include <bits/stdc++.h>
using namespace std;
void fast() {
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
}
void ran() {
	srand(chrono::steady_clock::now().time_since_epoch().count());
}
long long get_rand() {
	long long a = rand();
	long long b = rand();
	return a * (RAND_MAX + 1ll) + b;
}
void usaco() {
	freopen("problem.in", "r", stdin); 
	freopen("problem.out", "w", stdout);
}
template<typename T>
using min_pq = priority_queue<T, vector<T>, greater<T>>;
#define endl '\n'
// #define double long double
#define int long long
// const int MOD = 1000 * 1000 * 1000 + 7;
// const int MOD = 998244353;
// #define cerr if(0) cerr
#define debug(x) cerr << #x << ": " << x << endl;
 
int n, m;
const int MXN = 100005;
const int MXM = 200005;
int a[MXM], b[MXM], colour[MXM], price[MXM];
vector<pair<int, int>> adj[MXN];
map<int, int> adj_sum[MXN];
map<int, vector<pair<int, int>>> adjbycolour[MXN];
 
map<pair<int, int>, int> dist;
 
int getdist(int no, int co) {
	pair<int, int> tr = {no, co};
	auto f = dist.find(tr);
	if (f == dist.end()) return LLONG_MAX / 4;
	return f->second;
}
 
void setdist(int no, int co, int to) {
	dist[{no, co}] = to;
}
 
signed main() {
 
	ran(); fast();
 
	cin >> n >> m;
	for (int i=1; i<=m; i++) {
		cin >> a[i] >> b[i] >> colour[i] >> price[i];
		adj[a[i]].push_back({i, 1}); // connect it to the other side
		adj[b[i]].push_back({i, 0}); // connect it to the other side
		adj_sum[a[i]][colour[i]]+=price[i];
		adj_sum[b[i]][colour[i]]+=price[i];
		adjbycolour[a[i]][colour[i]].push_back({i, 1});
		adjbycolour[b[i]][colour[i]].push_back({i, 0});
	}
	
	min_pq<pair<int, pair<int, int>>> proc;
	proc.push({0, {1, -1}});
	
	while (!proc.empty()) {
		
		auto f = proc.top(); proc.pop();
		int di = f.first, no = f.second.first, co = f.second.second;
		
		if (getdist(no, co) < di) continue;
        setdist(no, co, di);
		// cout << no << " " << co << ": " << di << endl;
		
		if (co == -1) {
			// go anywhere tbh
			for (auto x: adj[no]) {
				int edge_num = x.first, ot = x.second;
				int other = a[edge_num];
				if (ot == 1) other = b[edge_num];
				// either recolour this one edge, paying price[edge_num]
				int od = getdist(other, -1); // you'll end somewhere without restriction
				if (di + price[edge_num] < od) {
					setdist(other, -1, di + price[edge_num]);
					proc.push({di + price[edge_num], {other, -1}});
				}
				// or recolour this edge, but pay later by forcing the same colour to be used next time
				od = getdist(other, colour[edge_num]);
				if (di < od) {
					setdist(other, colour[edge_num], di);
					proc.push({di, {other, colour[edge_num]}});
				}
				// or recolour all the other edges of this colour, paying the price here
				od = getdist(other, -1);
				int cost = adj_sum[no][colour[edge_num]] - price[edge_num];
				if (cost + di < od) {
					setdist(other, -1, cost + di);
					proc.push({cost+di, {other, -1}});
				}
			}
		}
		else {
			// you have agreed to take only certain coloured edges, and also to not recolour only the edge you take out of here
			// ie you must recolour all other edges of whatever colour you take
			int sm = adj_sum[no][co];
			for (auto x: adjbycolour[no][co]) {
				int edge_num = x.first, ot = x.second;
				int other = a[edge_num];
				if (ot == 1) other = b[edge_num];
				int od = sm - price[edge_num] + di;
				int curr = getdist(other, -1);
				if (od < curr) {
					setdist(other, -1, od);
					proc.push({od, {other, -1}});
				}
			}
		}
		
	}
	
	int res = getdist(n, -1);
	if (res == LLONG_MAX / 4) cout << -1 << endl;
	else cout << res << endl;
	
}

Compilation message

Main.cpp: In function 'void usaco()':
Main.cpp:18:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |  freopen("problem.in", "r", stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:19:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |  freopen("problem.out", "w", stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
# Verdict Execution time Memory Grader output
1 Correct 5 ms 11980 KB Output is correct
2 Correct 6 ms 11980 KB Output is correct
3 Correct 5 ms 11980 KB Output is correct
4 Correct 6 ms 11980 KB Output is correct
5 Correct 8 ms 12144 KB Output is correct
6 Correct 5 ms 11980 KB Output is correct
7 Correct 9 ms 12236 KB Output is correct
8 Correct 8 ms 12060 KB Output is correct
9 Correct 10 ms 12888 KB Output is correct
10 Correct 10 ms 12876 KB Output is correct
11 Correct 11 ms 12544 KB Output is correct
12 Correct 8 ms 12492 KB Output is correct
13 Correct 8 ms 12620 KB Output is correct
14 Correct 8 ms 12620 KB Output is correct
15 Correct 8 ms 12492 KB Output is correct
16 Correct 10 ms 12620 KB Output is correct
17 Correct 8 ms 12492 KB Output is correct
18 Correct 7 ms 12280 KB Output is correct
19 Correct 8 ms 12492 KB Output is correct
20 Correct 8 ms 12520 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 341 ms 38424 KB Output is correct
2 Correct 152 ms 25356 KB Output is correct
3 Correct 489 ms 38372 KB Output is correct
4 Correct 249 ms 30120 KB Output is correct
5 Correct 1565 ms 98840 KB Output is correct
6 Correct 1251 ms 86632 KB Output is correct
7 Correct 653 ms 70224 KB Output is correct
8 Correct 834 ms 70144 KB Output is correct
9 Correct 973 ms 70180 KB Output is correct
10 Correct 602 ms 57460 KB Output is correct
11 Correct 153 ms 37604 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 5 ms 11980 KB Output is correct
2 Correct 6 ms 11980 KB Output is correct
3 Correct 5 ms 11980 KB Output is correct
4 Correct 6 ms 11980 KB Output is correct
5 Correct 8 ms 12144 KB Output is correct
6 Correct 5 ms 11980 KB Output is correct
7 Correct 9 ms 12236 KB Output is correct
8 Correct 8 ms 12060 KB Output is correct
9 Correct 10 ms 12888 KB Output is correct
10 Correct 10 ms 12876 KB Output is correct
11 Correct 11 ms 12544 KB Output is correct
12 Correct 8 ms 12492 KB Output is correct
13 Correct 8 ms 12620 KB Output is correct
14 Correct 8 ms 12620 KB Output is correct
15 Correct 8 ms 12492 KB Output is correct
16 Correct 10 ms 12620 KB Output is correct
17 Correct 8 ms 12492 KB Output is correct
18 Correct 7 ms 12280 KB Output is correct
19 Correct 8 ms 12492 KB Output is correct
20 Correct 8 ms 12520 KB Output is correct
21 Correct 341 ms 38424 KB Output is correct
22 Correct 152 ms 25356 KB Output is correct
23 Correct 489 ms 38372 KB Output is correct
24 Correct 249 ms 30120 KB Output is correct
25 Correct 1565 ms 98840 KB Output is correct
26 Correct 1251 ms 86632 KB Output is correct
27 Correct 653 ms 70224 KB Output is correct
28 Correct 834 ms 70144 KB Output is correct
29 Correct 973 ms 70180 KB Output is correct
30 Correct 602 ms 57460 KB Output is correct
31 Correct 153 ms 37604 KB Output is correct
32 Correct 315 ms 37816 KB Output is correct
33 Correct 396 ms 37916 KB Output is correct
34 Correct 787 ms 61484 KB Output is correct
35 Correct 627 ms 51020 KB Output is correct
36 Correct 678 ms 59184 KB Output is correct
37 Correct 776 ms 64844 KB Output is correct
38 Correct 756 ms 76408 KB Output is correct
39 Correct 322 ms 44732 KB Output is correct
40 Correct 909 ms 71396 KB Output is correct
41 Correct 1055 ms 71708 KB Output is correct
42 Correct 940 ms 77064 KB Output is correct
43 Correct 334 ms 42864 KB Output is correct
44 Correct 899 ms 57148 KB Output is correct
45 Correct 729 ms 63028 KB Output is correct
46 Correct 559 ms 62260 KB Output is correct
47 Correct 653 ms 63108 KB Output is correct
48 Correct 1672 ms 104776 KB Output is correct