// #pragma GCC target ("avx,avx2,fma")
// #pragma GCC optimize ("Ofast,inline") // O1 - O2 - O3 - Os - Ofast
// #pragma GCC optimize ("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define rep(i, a, b) for (int i = (a); i < (b); ++i)
#define per(i, a, b) for (int i = (b - 1); i >= (a); --i)
#define trav(a, x) for (auto &a : x)
#define all(x) x.begin(), x.end()
#define sz(x) x.size()
#define pb push_back
#define debug(x) cout << #x << " = " << x << endl
#define umap unordered_map
#define uset unordered_set
typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef vector<ll> vll;
typedef vector<pll> vpll;
const int INF = 1'000'000'007;
int rows, cols, dist[2001][2001], parent[2001][2001];
int dr[] = {1, -1, 0, 0, 0};
int dc[] = {0, 0, 1, -1, 0};
string grid[2001];
bool valid(int row, int col) { return 0 <= row && row < rows && 0 <= col && col < cols; }
void path(int row, int col) {
int p = parent[row][col];
if (p == -1) return;
int nr = row - dr[p], nc = col - dc[p];
grid[nr][nc] = p;
path(nr, nc);
}
int main() {
cin.tie(0)->sync_with_stdio(0);
cin.exceptions(cin.failbit);
memset(dist, -1, sizeof(dist));
memset(parent, -1, sizeof(parent));
cin >> rows >> cols;
int sr, sc, er, ec;
rep(i, 0, rows) {
cin >> grid[i];
int j = 0;
trav(cell, grid[i]) {
if (cell == 'o') {
sr = i;
sc = j;
} else if (cell == 'x') {
er = i;
ec = j;
}
cell = cell == 'v' ? 0 : cell == '^' ? 1
: cell == '>' ? 2
: cell == '<' ? 3
: 4;
++j;
}
}
deque<ii> q;
dist[sr][sc] = 0;
rep(i, 0, 4) if (valid(sr + dr[i], sc + dc[i])) {
q.emplace_front(sr + dr[i], sc + dc[i]);
dist[sr + dr[i]][sc + dc[i]] = 0;
}
while (!q.empty()) {
int row, col;
tie(row, col) = q.front();
// cout << "row = " << row << " col = " << col << " dist = " << dist[row][col] << endl;
q.pop_front();
if (!dist[row][col] == -2) continue;
if (row == er && col == ec) {
cout << dist[row][col] << endl;
path(row, col);
break;
}
int cell = grid[row][col];
int nr = row + dr[cell], nc = col + dc[cell];
if (valid(nr, nc)) {
if (dist[nr][nc] == -1 || dist[row][col] < dist[nr][nc]) {
dist[nr][nc] = dist[row][col];
q.emplace_front(nr, nc);
parent[nr][nc] = cell;
}
}
rep(i, 0, 4) {
nr = row + dr[i], nc = col + dc[i];
if (!valid(nr, nc) || dist[nr][nc] != -1) continue;
dist[nr][nc] = dist[row][col] + 1;
q.emplace_back(nr, nc);
parent[nr][nc] = i;
}
dist[row][col] = -2;
}
rep(i, 0, rows) {
trav(cell, grid[i]) cell = cell == 0 ? 'v' : cell == 1 ? '^'
: cell == 2 ? '>'
: cell == 3 ? '<'
: '.';
}
grid[sr][sc]='o';
grid[er][ec]='x';
rep(i, 0, rows) cout << grid[i] << endl;
return 0;
}
Compilation message
Main.cpp: In function 'int main()':
Main.cpp:90:29: warning: logical not is only applied to the left hand side of comparison [-Wlogical-not-parentheses]
90 | if (!dist[row][col] == -2) continue;
| ^~
Main.cpp:90:13: note: add parentheses around left hand side expression to silence this warning
90 | if (!dist[row][col] == -2) continue;
| ^~~~~~~~~~~~~~~
| ( )
Main.cpp:90:29: warning: comparison of constant '-2' with boolean expression is always false [-Wbool-compare]
90 | if (!dist[row][col] == -2) continue;
| ~~~~~~~~~~~~~~~~^~~~~
Main.cpp:126:16: warning: 'ec' may be used uninitialized in this function [-Wmaybe-uninitialized]
126 | grid[er][ec]='x';
| ^
Main.cpp:79:27: warning: 'sc' may be used uninitialized in this function [-Wmaybe-uninitialized]
79 | rep(i, 0, 4) if (valid(sr + dr[i], sc + dc[i])) {
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:79:27: warning: 'sr' may be used uninitialized in this function [-Wmaybe-uninitialized]
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
13 ms |
31692 KB |
Output is correct |
| 2 |
Correct |
14 ms |
31608 KB |
Output is correct |
| 3 |
Correct |
12 ms |
31704 KB |
Output is correct |
| 4 |
Correct |
12 ms |
31692 KB |
Output is correct |
| 5 |
Correct |
13 ms |
31668 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
13 ms |
31692 KB |
Output is correct |
| 2 |
Correct |
14 ms |
31608 KB |
Output is correct |
| 3 |
Correct |
12 ms |
31704 KB |
Output is correct |
| 4 |
Correct |
12 ms |
31692 KB |
Output is correct |
| 5 |
Correct |
13 ms |
31668 KB |
Output is correct |
| 6 |
Correct |
29 ms |
32716 KB |
Output is correct |
| 7 |
Correct |
31 ms |
33604 KB |
Output is correct |
| 8 |
Correct |
79 ms |
34628 KB |
Output is correct |
| 9 |
Correct |
98 ms |
38792 KB |
Output is correct |
| 10 |
Correct |
169 ms |
38156 KB |
Output is correct |
| 11 |
Correct |
194 ms |
44472 KB |
Output is correct |
