From 1017ff846def1ce2f9f9ae4b4ec1ccea501709b5 Mon Sep 17 00:00:00 2001
From: Ren Baoshuo <i@baoshuo.ren>
Date: Thu, 6 Aug 2020 14:35:45 +0800
Subject: [PATCH] =?UTF-8?q?P5731=20=E3=80=90=E6=B7=B1=E5=9F=BA5.=E4=B9=A06?=
 =?UTF-8?q?=E3=80=91=E8=9B=87=E5=BD=A2=E6=96=B9=E9=98=B5?=
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R36471603
---
 problem/P5731/P5731.cpp | 64 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 problem/P5731/P5731.cpp

diff --git a/problem/P5731/P5731.cpp b/problem/P5731/P5731.cpp
new file mode 100644
index 00000000..d25bfb4b
--- /dev/null
+++ b/problem/P5731/P5731.cpp
@@ -0,0 +1,64 @@
+// R36471603
+
+#include<bits/stdc++.h>
+
+using namespace std;
+
+int n, k, a[15][15], ax, ay;
+
+
+int main() {
+    k = ax = 1;
+
+    scanf("%d", &n);
+    
+    /**
+     * ax, ay+1 -> 右侧
+     * ax, ay-1 -> 左侧
+     * ax+1, ay -> 下方
+     * ax-1, ay -> 上方
+     * 
+     * 0 --- 1 ---------- ay ----------> n
+     * | +------+------+------+------+------+
+     * 1 |      |      | ax-1 |      |      |
+     * | |      |      |  ay  |      |      |
+     * | +------+------+------+------+------+
+     * a |      |  ax  |  ax  |  ax  |      |
+     * x |      | ay-1 |  ay  | ay+1 |      |
+     * | +------+------+------+------+------+
+     * | |      |      | ax+1 |      |      |
+     * | |      |      |  ay  |      |      |
+     * | +------+------+------+------+------+
+     * | |      |      |      |      |      |
+     * | |      |      |      |      |      |
+     * | +------+------+------+------+------+
+     * | |      |      |      |      |      |
+     * n |      |      |      |      |      | n
+     *   +------+------+------+------+------+
+     *                                   n
+     */
+
+    while(k <= n*n) {
+        while(ay < n && !a[ax][ay+1]) { // 右侧  不过边界 && 未填数
+            a[ax][++ay] = k++;
+        }
+        while(ax < n && !a[ax+1][ay]) { // 下方  不过边界 && 未填数
+            a[++ax][ay] = k++;
+        }
+        while(ay > 1 && !a[ax][ay-1]) { // 左侧  不过边界 && 未填数
+            a[ax][--ay] = k++;
+        }
+        while(ax > 1 && !a[ax-1][ay]) { // 上方  不过边界 && 未填数
+            a[--ax][ay] = k++;
+        }
+    }
+
+    for(int i = 1 ; i <= n ; i++) {
+        for(int j = 1 ; j <= n ; j++) {
+            printf("%3d", a[i][j]);
+        }
+        printf("\n");
+    }
+
+    return 0;
+}