Import Upstream version 0.5c

1 files changed, 37 insertions, 0 deletions

diff --git a/nqueens.c b/nqueens.c
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--- /dev/null
+++ b/nqueens.c
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+/*
+ * N-Queens Problem Solver
+ * Found somewhere on the Internet; can't remember where. Possibly Wikipedia.
+ */
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+#define QUEENS 11
+
+int row[QUEENS];
+
+bool safe(int x, int y)
+{
+    int i;
+    for (i = 1; i <= y; i++)
+	if (row[y - i] == x || row[y - i] == x - i || row[y - i] == x + i)
+	    return false;
+    return true;
+}
+
+int nqueens(int y)
+{
+    int x;
+    
+    for (x = 0; x < QUEENS; x++) {
+	if (safe((row[y - 1] = x), y - 1)) {
+	    if (y < QUEENS) {
+		nqueens(y + 1);
+	    } else {
+	        break;
+            }
+        }
+    }
+    
+    return 0;
+}