#593. 八皇后问题

https://sjzezoj.com/submission/44617

S2OJ/593/593.cpp

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+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n, ans, a[105];
+bool col[105], dg[105], udg[105];
+
+void dfs(int i) {
+    if (i > n) {
+        if (ans < 3) {
+            for (int i = 1; i < n; i++) {
+                cout << a[i] << ' ';
+            }
+            cout << a[n] << endl;
+        }
+        ans++;
+        return;
+    }
+    for (int j = 1; j <= n; j++) {
+        if (!col[j] && !dg[i + j] && !udg[n - j + i]) {
+            a[i] = j;
+            col[j] = dg[i + j] = udg[n - j + i] = true;
+            dfs(i + 1);
+            col[j] = dg[i + j] = udg[n - j + i] = false;
+        }
+    }
+}
+
+int main() {
+    cin >> n;
+    dfs(1);
+    cout << ans << endl;
+    return 0;
+}