Submission #970600

#	Time	Username	Problem	Language	Result	Execution time	Memory
970600		dosts	Mecho (IOI09_mecho)	C++17	14 / 100	181 ms	12020 KiB

mecho

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
#define sp << " " << 
#define int long long
#define vi vector<int>
#define pb push_back
#define F(xxx,yyy) for (int xxx=1;xxx<=yyy;xxx++)
#define pii pair<int,int>
#define ordered_set tree<pii, null_type, less<pii>, rb_tree_tag, tree_order_statistics_node_update>
 
 
void solve() {
	int n,k;
	cin >> n >> k;
	char grid[n+1][n+1];
	queue<pii> q;
	vector<vi> bee(n+1,vi(n+1,-1));
	int sx,sy,hx,hy;
	F(i,n) {
		string s;
		cin >> s;
		F(j,n) {
			grid[i][j]  = s[j-1];
			if (s[j-1] == 'H') {
				q.push({i,j});
				bee[i][j] = 0;
			}
			if (s[j-1] == 'D') {
				hx = i;
				hy = j;
			}
			if (s[j-1] == 'M') {
				sx = i;
				sy = j;
			}
		}
	}
	vi dx = {1,0,-1,0};
	vi dy = {0,1,0,-1};
	while (!q.empty()) {
		pii f = q.front();
		q.pop();
		int x = f.first;
		int y = f.second;
		for (int i=0;i<4;i++) { 
			int gx = x+dx[i];
			int gy = y+dy[i];
			if (gx < 1 || gx > n) continue;
			if (gy < 1 || gy > n) continue;
			if (grid[gx][gy] == 'T') continue;
			if (grid[gx][gy] == 'D') continue;
			if (bee[gx][gy] != -1) continue;
			bee[gx][gy] = bee[x][y]+1;
			q.push({gx,gy});
		}
	}
	int l = 0;
	int r = 1e9;
	while (l<=r) {
		int w = (l+r) >> 1;
		if (w >= bee[sx][sy]) {
			r = w-1;
			continue;
		}
		vector<vi> dist(n+1,vi(n+1,-1));
		dist[sx][sy] = 0;
		q.push({sx,sy});
		while (!q.empty()) {
			pii f = q.front();
			q.pop();
			int x = f.first;
			int y = f.second;
			for (int i=0;i<4;i++) { 
				int gx = x+dx[i];
				int gy = y+dy[i];
				if (gx < 1 || gx > n) continue;
				if (gy < 1 || gy > n) continue;
				if (grid[gx][gy] == 'T') continue;
				if (dist[gx][gy] != -1) continue;
				if (bee[gx][gy] != -1 && bee[gx][gy] < w+((dist[x][y]+k-1)/k)+1) continue;
				dist[gx][gy] = dist[x][y]+1;
				q.push({gx,gy});
			}
		}
		if (dist[hx][hy]!=-1) l = w+1;
		else r = w-1;
	}
	cout << r << endl;
}       
                 
                 
                             
signed main() { 
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    int t = 1;
    //cin >> t; 
    while (t --> 0) solve();
}

Compilation message (stderr)

mecho.cpp: In function 'void solve()':
mecho.cpp:63:22: warning: 'sy' may be used uninitialized in this function [-Wmaybe-uninitialized]
   63 |   if (w >= bee[sx][sy]) {
      |                      ^
mecho.cpp:63:18: warning: 'sx' may be used uninitialized in this function [-Wmaybe-uninitialized]
   63 |   if (w >= bee[sx][sy]) {
      |                  ^
mecho.cpp:87:14: warning: 'hx' may be used uninitialized in this function [-Wmaybe-uninitialized]
   87 |   if (dist[hx][hy]!=-1) l = w+1;
      |              ^
mecho.cpp:87:18: warning: 'hy' may be used uninitialized in this function [-Wmaybe-uninitialized]
   87 |   if (dist[hx][hy]!=-1) l = w+1;
      |                  ^

• Subtask 1: 14 / 100