From 6394dcb8190b1c5b7d46041ccf1e95a3ceac426b Mon Sep 17 00:00:00 2001
From: Camden Dixie O'Brien <cobrien@witekio.com>
Date: Thu, 6 Mar 2025 22:05:03 +0000
Subject: [PATCH] Probe known-safe tiles

---
 main.c | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/main.c b/main.c
index e1d0ecd..b2ac62b 100644
--- a/main.c
+++ b/main.c
@@ -5,6 +5,7 @@
 
 #include "puzz.h"
 
+#include <assert.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -26,6 +27,23 @@ static void setadj(puzz_t field, int x, int y, uint8_t from, uint8_t to)
 	}
 }
 
+static void getadj(puzz_t field, int *x, int *y, uint8_t val)
+{
+	for (int yp = *y - 1; yp < *y + 2; ++yp) {
+		for (int xp = *x - 1; xp < *x + 2; ++xp) {
+			if (xp < 0 || xp >= WIDTH || yp < 0 || yp >= HEIGHT
+			    || (xp == *x && yp == *y))
+				continue;
+			if (field[xp][yp] == val) {
+				*x = xp;
+				*y = yp;
+				return;
+			}
+		}
+	}
+	assert(false);
+}
+
 int main(void)
 {
 	struct timeval tv;
@@ -46,6 +64,7 @@ int main(void)
 		int x = rand() % WIDTH;
 		int y = rand() % HEIGHT;
 
+	probe:
 		if (probe(x, y, field) == DEAD) {
 			field[x][y] = KILLER;
 			break;
@@ -58,9 +77,16 @@ int main(void)
 
 				const int mines = countadj(field, x, y, MINE);
 				const int unknowns = countadj(field, x, y, UNKNOWN);
+				if (unknowns == 0)
+					continue;
 
-				if (unknowns > 0 && mines + unknowns == field[x][y])
+				if (mines + unknowns == field[x][y])
 					setadj(field, x, y, UNKNOWN, MINE);
+
+				if (mines == field[x][y]) {
+					getadj(field, &x, &y, UNKNOWN);
+					goto probe;
+				}
 			}
 		}