update

poj/3984.maze/main.cc

@@ -0,0 +1,60 @@
+#include <algorithm>
+#include <cstdio>
+#include <queue>
+#include <string>
+#include <vector>
+
+using namespace std;
+
+const int N = 5;
+const int dx[4] = {1, 0, -1, 0};
+const int dy[4] = {0, 1, 0, -1};
+
+char pos[7];
+
+struct Grid {
+  bool way;
+  int row;
+  int col;
+  Grid *pre;
+};
+
+Grid maze[N][N];
+
+int main() {
+  for (int i = 0, k; i < N; i++) {
+    for (int j = 0; j < N; j++) {
+      scanf("%d", &k);
+      maze[i][j].way = k == 0;
+      maze[i][j].row = i;
+      maze[i][j].col = j;
+      maze[i][j].pre = NULL;
+    }
+  }
+  queue<Grid> q;
+  q.push(maze[0][0]);
+  while (q.size() != 0) {
+    Grid &g = q.front();
+    q.pop();
+    if (g.col == N - 1 && g.row == N - 1) break;
+    for (int i = 0, nx, ny; i < 4; i++) {
+      nx = g.row + dx[i];
+      ny = g.col + dy[i];
+      if (nx < 0 || N <= nx || ny < 0 || N <= ny) continue;
+      Grid &ng = maze[nx][ny];
+      if (!ng.way || ng.pre != NULL) continue;
+      ng.pre = &g;
+      q.push(ng);
+    }
+  }
+  Grid *cur = &maze[N - 1][N - 1];
+  vector<string> path;
+  while (cur != NULL) {
+    sprintf(pos, "(%d, %d)", cur->row, cur->col);
+    path.push_back(pos);
+    cur = cur->pre;
+  }
+  for (vector<string>::reverse_iterator cur = path.rbegin(); cur != path.rend(); ++cur)
+    printf("%s\n", cur->c_str());
+  return 0;
+}