66 lines
1.7 KiB
C++
66 lines
1.7 KiB
C++
#include <bits/stdc++.h>
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using namespace std;
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const int N = 40;
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int n;
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int a[N][N];
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int b[N][N];
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int dx[] = {0, 0, -1, 1};
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int dy[] = {-1, 1, 0, 0};
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struct coord {
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int x, y;
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};
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//广度优先搜索
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void bfs(int x, int y) {
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queue<coord> q;
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q.push({x, y});
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while (!q.empty()) {
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coord p = q.front();
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q.pop();
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b[p.x][p.y] = -1;
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for (int i = 0; i < 4; i++) {
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int x1 = p.x + dx[i], y1 = p.y + dy[i];
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if (b[x1][y1] >= 0 && x1 >= 1 && x1 <= n && y1 >= 1 && y1 <= n && a[x1][y1] == 0) {
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q.push({x1, y1});
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b[x1][y1] = -1;
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}
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}
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}
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}
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int main() {
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//读入地图
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cin >> n;
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for (int i = 1; i <= n; i++)
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for (int j = 1; j <= n; j++) {
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cin >> a[i][j];
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b[i][j] = a[i][j];
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}
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//思路：从边缘（四条外边），找0，然后BFS找出所有区域，这些区域就是不被圈起来的范围，进行标识，再取反
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for (int i = 1; i <= n; i++)
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if (a[1][i] == 0) bfs(1, i); //第一行
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for (int i = 1; i <= n; i++)
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if (a[i][1] == 0) bfs(i, 1); //第一列
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for (int i = 1; i <= n; i++)
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if (a[n][i] == 0) bfs(n, i); //最后一行
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for (int i = 1; i <= n; i++)
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if (a[i][n] == 0) bfs(i, n); //最后一列
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//输出
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for (int i = 1; i <= n; i++) {
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for (int j = 1; j <= n; j++) {
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if (b[i][j] == -1) cout << 0 << " ";
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else if (b[i][j] == 0) cout << 2 << " ";
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else cout << b[i][j] << " ";
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}
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cout << endl;
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}
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return 0;
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} |