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62 lines
1.3 KiB
C++
62 lines
1.3 KiB
C++
#include <bits/stdc++.h>
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using namespace std;
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const int dx[] = {0, 0, 0, -1, 1};
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const int dy[] = {0, 1, -1, 0, 0};
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struct node {
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int x, y, t;
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node() {
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x = y = t = 0;
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}
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node(int _x, int _y, int _t) {
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x = _x, y = _y, t = _t;
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}
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};
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int n, x, y, t, m[305][305], f[305][305];
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int main() {
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memset(m, 0x3f, sizeof(m));
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cin >> n;
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for (int i = 1; i <= n; i++) {
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cin >> x >> y >> t;
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m[x][y] = min(m[x][y], t);
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for (int j = 1; j <= 4; j++) {
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int xx = x + dx[j];
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int yy = y + dy[j];
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if (xx < 0 || yy < 0) continue;
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m[xx][yy] = min(m[xx][yy], t);
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}
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}
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queue<node> q;
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f[0][0] = 1;
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if (m[0][0] == 0x3f3f3f3f) {
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cout << 0 << endl;
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return 0;
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}
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q.push(node(0, 0, 0));
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while (!q.empty()) {
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int xx = q.front().x;
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int yy = q.front().y;
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int tt = q.front().t;
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q.pop();
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for (int i = 1; i <= 4; i++) {
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int u = xx + dx[i];
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int v = yy + dy[i];
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if (f[u][v] || u < 0 || v < 0 || tt + 1 >= m[u][v]) continue;
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if (m[u][v] == 0x3f3f3f3f) {
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cout << tt + 1 << endl;
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return 0;
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}
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q.push(node(u, v, tt + 1));
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f[u][v] = 1;
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}
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}
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cout << -1 << endl;
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return 0;
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}
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