new file: 31.cpp

31.cpp

@@ -0,0 +1,53 @@
+// 116
+#include <bits/stdc++.h>
+using namespace std;
+bool dddd[5][5];
+bool hang[5];
+bool lie[5];
+bool chosen[5][5];
+vector<pair<int, int>> cc, anss;
+void in()
+{
+    for (int i = 0; i < 4; ++i)
+    {
+        for (int j = 0; j < 4; ++j)
+            if (getchar() == '+')
+                dddd[i][j] = 1;
+        getchar();
+    }
+}
+void dfs(int x, int y)
+{
+    if (x == 4)
+    {
+        for (int i = 0; i < 4; ++i)
+        {
+            for (int j = 0; j < 4; ++j)
+            {
+                if (hang[i] ^ lie[j] ^ dddd[i][j] ^ chosen[i][j])
+                    return;
+            }
+        }
+        if (anss.empty() || (int)cc.size() < anss.size())
+        {
+            anss = cc;
+        }
+        return;
+    }
+    hang[x] = !hang[x], lie[y] = !lie[y], chosen[x][y] = 1;
+    cc.push_back({x, y});
+    dfs((y == 3) ? x + 1 : x, (y == 3) ? 0 : y + 1);
+    hang[x] = !hang[x], lie[y] = !lie[y], chosen[x][y] = 0;
+    cc.pop_back();
+    dfs((y == 3) ? x + 1 : x, (y == 3) ? 0 : y + 1);
+}
+int main()
+{
+    in();
+    dfs(0, 0);
+    printf("%d\n", anss.size());
+    for (int i = 0; i < (int)anss.size(); ++i)
+    {
+        printf("%d %d\n", anss[i].first + 1, anss[i].second + 1);
+    }
+}