oj.uz

Submission #790974

# Submission time Handle Problem Language Result Execution time Memory
790974 2023-07-23T10:18:56 Z Gray Mecho (IOI09_mecho) C++17
100 / 100
 181 ms 11320 KB 
// Source: https://usaco.guide/general/io
 
#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define ln "\n"
#define ff first
#define ss second
#define INF 2e9
using namespace std;
 
void solve(){
	ll n, s; cin >> n >> s;
	vector<vector<char>> gr(n, vector<char>(n));
	vector<pair<ll, ll>> hvs;
	pair<ll, ll> bcor, hcor;
	for (ll i=0; i<n; i++){
		for (ll j=0; j<n; j++){
			cin >> gr[i][j];
			if (gr[i][j]=='H'){
				hvs.push_back({i, j});
			}else if (gr[i][j]=='M'){
				bcor = {i, j};
			}else if (gr[i][j]=='D'){
				hcor = {i, j};
			}
		}
	}
	vector<vector<ll>> hpath(n, vector<ll>(n, INF));
	
	//Generate HPATH in O(N^2)
	queue<pair<ll, ll>> q;
	for (auto hive:hvs){
		hpath[hive.ff][hive.ss]=0;
		q.push({hive.ff, hive.ss});
	}
	while (!q.empty()){
		pair<ll, ll> hive = q.front();
		q.pop();
		long long xsh, ysh;
		xsh=1; ysh=0;
		if ((hive.ff+xsh<n and hive.ff+xsh>=0) and hpath[hive.ff+xsh][hive.ss+ysh]==INF and (hive.ss+ysh<n and hive.ss+ysh>=0) and (gr[hive.ff+xsh][hive.ss+ysh]=='G' or gr[hive.ff+xsh][hive.ss+ysh]=='M')){
			q.push({hive.ff+xsh, hive.ss+ysh});
			hpath[hive.ff+xsh][hive.ss+ysh]=hpath[hive.ff][hive.ss]+1;
		}
		xsh=-1, ysh=0;
		if ((hive.ff+xsh<n and hive.ff+xsh>=0) and hpath[hive.ff+xsh][hive.ss+ysh]==INF and (hive.ss+ysh<n and hive.ss+ysh>=0) and (gr[hive.ff+xsh][hive.ss+ysh]=='G' or gr[hive.ff+xsh][hive.ss+ysh]=='M')){
			q.push({hive.ff+xsh, hive.ss+ysh});
			hpath[hive.ff+xsh][hive.ss+ysh]=hpath[hive.ff][hive.ss]+1;
		}
		xsh=0; ysh=1;
		if ((hive.ff+xsh<n and hive.ff+xsh>=0) and hpath[hive.ff+xsh][hive.ss+ysh]==INF and (hive.ss+ysh<n and hive.ss+ysh>=0) and (gr[hive.ff+xsh][hive.ss+ysh]=='G' or gr[hive.ff+xsh][hive.ss+ysh]=='M')){
			q.push({hive.ff+xsh, hive.ss+ysh});
			hpath[hive.ff+xsh][hive.ss+ysh]=hpath[hive.ff][hive.ss]+1;
		}
		xsh=0; ysh=-1;
		if ((hive.ff+xsh<n and hive.ff+xsh>=0) and hpath[hive.ff+xsh][hive.ss+ysh]==INF and (hive.ss+ysh<n and hive.ss+ysh>=0) and (gr[hive.ff+xsh][hive.ss+ysh]=='G' or gr[hive.ff+xsh][hive.ss+ysh]=='M')){
			q.push({hive.ff+xsh, hive.ss+ysh});
			hpath[hive.ff+xsh][hive.ss+ysh]=hpath[hive.ff][hive.ss]+1;
		}
	}
 
	auto bfs2 = [&](ll wt) -> bool{
		pair<ll, ll> cord = bcor;
		if (hpath[cord.ff][cord.ss]-1<wt) {
			// cout << "Fail at start: " << hpath[cord.ff][cord.ss] << " <: " << cord.ff << "," << cord.ss << " -> " << wt << ln; 
			return 0;
		}
		vector<vector<ll>> vi(n, vector<ll>(n, INF));
		queue<pair<ll, ll>> q;
		q.push(cord);
		vi[cord.ff][cord.ss]=wt;
		while (!q.empty()){
			pair<ll, ll> cur = q.front();
			q.pop();
			// cout << "(" << cur.ss << "," << cur.ff << ") -> hpath=" << hpath[cur.ff][cur.ss] << "; mdist=" << vi[cur.ff][cur.ss]-wt << "; enters at=" << (((vi[cur.ff][cur.ss]-wt)/(ld)s)+wt) << "; " << " bee comes in=" << hpath[cur.ff][cur.ss] << ln;
			if (cur.ff>0 and vi[cur.ff-1][cur.ss]==INF and gr[cur.ff-1][cur.ss]!='T' and gr[cur.ff-1][cur.ss]!='H' and (((vi[cur.ff][cur.ss]-wt+1)/s)+wt)<(hpath[cur.ff-1][cur.ss])){
				// cout << (hpath[cur.ff-1][cur.ss]-(vi[cur.ff][cur.ss]-wt)/s-1) << " <- " << cur.ss << "," << cur.ff << " to U: cmx " << vi[cur.ff][cur.ss] << " Dist from bear: " << vi[cur.ff][cur.ss]-wt+1 << ln;
				vi[cur.ff-1][cur.ss]=vi[cur.ff][cur.ss]+1;
				q.push({cur.ff-1, cur.ss});
			}
			if (cur.ss>0 and vi[cur.ff][cur.ss-1]==INF and gr[cur.ff][cur.ss-1]!='T' and gr[cur.ff][cur.ss-1]!='H' and (((vi[cur.ff][cur.ss]-wt+1)/s)+wt)<(hpath[cur.ff][cur.ss-1])){
				// cout << (hpath[cur.ff][cur.ss-1]-(vi[cur.ff][cur.ss]-wt)/s-1) << " <- " << cur.ss << "," << cur.ff << " to L: cmx " << vi[cur.ff][cur.ss] << " Dist from bear: " << vi[cur.ff][cur.ss]-wt+1 << ln;
				vi[cur.ff][cur.ss-1]=vi[cur.ff][cur.ss]+1;
				q.push({cur.ff, cur.ss-1});
			}
			if (cur.ff+1<n and vi[cur.ff+1][cur.ss]==INF and gr[cur.ff+1][cur.ss]!='T' and gr[cur.ff+1][cur.ss]!='H' and (((vi[cur.ff][cur.ss]-wt+1)/s)+wt)<(hpath[cur.ff+1][cur.ss])){
				// cout << (hpath[cur.ff+1][cur.ss]-(vi[cur.ff][cur.ss]-wt)/s-1) << " <- " << cur.ss << "," << cur.ff << " to D: cmx " << vi[cur.ff][cur.ss] << " Dist from bear: " << vi[cur.ff][cur.ss]-wt+1 << ln;
				vi[cur.ff+1][cur.ss]=vi[cur.ff][cur.ss]+1;
				q.push({cur.ff+1, cur.ss});
			}
			if (cur.ss+1<n and vi[cur.ff][cur.ss+1]==INF and gr[cur.ff][cur.ss+1]!='T' and gr[cur.ff][cur.ss+1]!='H' and (((vi[cur.ff][cur.ss]-wt+1)/s)+wt)<(hpath[cur.ff][cur.ss+1])){
				// cout << (hpath[cur.ff][cur.ss+1]-(vi[cur.ff][cur.ss]+1-wt)/s-1) << " <- " << cur.ss << "," << cur.ff << " to R: cmx " << vi[cur.ff][cur.ss] << " Dist from bear: " << vi[cur.ff][cur.ss]-wt+1 << ln;
				vi[cur.ff][cur.ss+1]=vi[cur.ff][cur.ss]+1;
				q.push({cur.ff, cur.ss+1});
			}
		}
		if (vi[hcor.ff][hcor.ss]<INF) return 1;
		else return 0;
	};
	ll l=-1, r=n*n+1;
	while (l+1<r){
		ll mid = (l+r)/2;
		if (bfs2(mid)) {
			l=mid;
			// cout << mid << " with T" << ln;
		}
		else {
			r=mid;
			// cout << mid << " with F" << ln;
		}
	}
	cout << l << ln;
}
 
int main() {
	ll t=1; 
	// cin >> t;
	while (t--) solve();
}

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 76 ms 11216 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 212 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 1 ms 212 KB Output is correct
12 Correct 1 ms 340 KB Output is correct
13 Correct 1 ms 340 KB Output is correct
14 Correct 1 ms 340 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 1 ms 304 KB Output is correct
17 Correct 1 ms 212 KB Output is correct
18 Correct 1 ms 300 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct
21 Correct 1 ms 212 KB Output is correct
22 Correct 1 ms 304 KB Output is correct
23 Correct 1 ms 340 KB Output is correct
24 Correct 1 ms 340 KB Output is correct
25 Correct 1 ms 340 KB Output is correct
26 Correct 1 ms 340 KB Output is correct
27 Correct 1 ms 304 KB Output is correct
28 Correct 1 ms 304 KB Output is correct
29 Correct 1 ms 340 KB Output is correct
30 Correct 1 ms 340 KB Output is correct
31 Correct 1 ms 340 KB Output is correct
32 Correct 1 ms 340 KB Output is correct
33 Correct 10 ms 2492 KB Output is correct
34 Correct 9 ms 2492 KB Output is correct
35 Correct 19 ms 2612 KB Output is correct
36 Correct 15 ms 3136 KB Output is correct
37 Correct 13 ms 3124 KB Output is correct
38 Correct 22 ms 3140 KB Output is correct
39 Correct 15 ms 3860 KB Output is correct
40 Correct 15 ms 3796 KB Output is correct
41 Correct 32 ms 3884 KB Output is correct
42 Correct 20 ms 4644 KB Output is correct
43 Correct 19 ms 4668 KB Output is correct
44 Correct 37 ms 4668 KB Output is correct
45 Correct 26 ms 5544 KB Output is correct
46 Correct 24 ms 5524 KB Output is correct
47 Correct 43 ms 5500 KB Output is correct
48 Correct 28 ms 6492 KB Output is correct
49 Correct 27 ms 6476 KB Output is correct
50 Correct 63 ms 6500 KB Output is correct
51 Correct 33 ms 7588 KB Output is correct
52 Correct 30 ms 7504 KB Output is correct
53 Correct 70 ms 7536 KB Output is correct
54 Correct 44 ms 8828 KB Output is correct
55 Correct 36 ms 8696 KB Output is correct
56 Correct 92 ms 8672 KB Output is correct
57 Correct 45 ms 9932 KB Output is correct
58 Correct 46 ms 9960 KB Output is correct
59 Correct 86 ms 9888 KB Output is correct
60 Correct 51 ms 11280 KB Output is correct
61 Correct 46 ms 11244 KB Output is correct
62 Correct 111 ms 11176 KB Output is correct
63 Correct 107 ms 11184 KB Output is correct
64 Correct 181 ms 11196 KB Output is correct
65 Correct 149 ms 11196 KB Output is correct
66 Correct 119 ms 11196 KB Output is correct
67 Correct 123 ms 11196 KB Output is correct
68 Correct 61 ms 11216 KB Output is correct
69 Correct 72 ms 11308 KB Output is correct
70 Correct 54 ms 11272 KB Output is correct
71 Correct 61 ms 11248 KB Output is correct
72 Correct 53 ms 11212 KB Output is correct
73 Correct 41 ms 11248 KB Output is correct
74 Correct 61 ms 11280 KB Output is correct
75 Correct 68 ms 11316 KB Output is correct
76 Correct 95 ms 11264 KB Output is correct
77 Correct 63 ms 11224 KB Output is correct
78 Correct 72 ms 11300 KB Output is correct
79 Correct 57 ms 11276 KB Output is correct
80 Correct 63 ms 11268 KB Output is correct
81 Correct 70 ms 11320 KB Output is correct
82 Correct 64 ms 11272 KB Output is correct
83 Correct 74 ms 11256 KB Output is correct
84 Correct 74 ms 11272 KB Output is correct
85 Correct 80 ms 11248 KB Output is correct
86 Correct 72 ms 11256 KB Output is correct
87 Correct 72 ms 11280 KB Output is correct
88 Correct 77 ms 11244 KB Output is correct
89 Correct 73 ms 11224 KB Output is correct
90 Correct 75 ms 11228 KB Output is correct
91 Correct 80 ms 11244 KB Output is correct
92 Correct 98 ms 11292 KB Output is correct