Initial commit

15lanqiao/test6.cpp

@@ -0,0 +1,57 @@
+#include<bits/stdc++.h>
+using namespace std;
+const int N = 20;
+int a[N][N];    // 迷宫数组
+int vis[N][N];  // 标记数组
+int n, k;
+  // 方向数组 0  1  2   3  4  5  6   7
+int dx[] = {-1, -1, 0, 1, 1, 1, 0, -1};
+int dy[] = { 0, 1, 1, 1, 0, -1, -1, -1};
+string res; // 结果字符串
+
+void dfs(int x, int y, int pre, string s, int dep){
+    if(x == n && y == n && dep == n*n){
+        if(res.empty()) res = s;    // 字典需最小的
+        return;
+    }
+    for(int i = 0; i < 8; i++){
+        int bx = x + dx[i], by = y + dy[i];
+        if(bx < 1 || bx > n || by < 1 || by > n) continue;
+        if(vis[bx][by]) continue;
+        // 防止交叉搜索
+        if(i == 1 && vis[x-1][y] && vis[x][y+1]) continue;
+        else if(i == 3 && vis[x+1][y] && vis[x][y+1]) continue;
+        else if(i == 5 && vis[x+1][y] && vis[x][y-1]) continue;
+        else if(i == 7 && vis[x-1][y] && vis[x][y-1]) continue;
+        // 保证路径数值为0 1 ... k-1
+        if((a[bx][by] < k && a[bx][by] == pre + 1) || (pre + 1 == k && a[bx][by] == 0)){
+            vis[bx][by] = 1;
+            dfs(bx, by, a[bx][by], s + to_string(i), dep + 1);
+            // 最优性剪枝
+            if(!res.empty()) return;
+            vis[bx][by] = 0; //回溯
+        } 
+    }
+}
+
+int main() {
+	cin >> n >> k;
+    for(int i = 1; i <= n; i++){
+        for(int j = 1; j <= n; j++){
+            cin >> a[i][j];
+        }
+    }
+    string emp;
+    vis[1][1] = 1;
+    dfs(1, 1, 0, emp, 1);
+    if(res.empty()) cout << -1 << endl;
+    else cout << res << endl;
+	return 0;
+}
+
+/* test samples
+3 3
+0 2 0
+1 1 1
+2 0 2
+*/