🐜 Study: 2차원 동전 뒤집기

Author: ing-eoking

ing-eoking/2차원 동전 뒤집기.cc

@@ -0,0 +1,50 @@
+#include <iostream>
+#include <vector>
+#include <string>
+
+using namespace std;
+
+int N, M;
+
+void reverse(vector<vector<int>> &m, int r, int c, int dr, int dc) {
+    while (r < N && c < M) {
+        m[r][c] = !m[r][c];
+        r += dr; c += dc;
+    }
+}
+
+bool equal(vector<vector<int>> &a, vector<vector<int>> &b) {
+    for (int i = 0; i < N; i++)
+        for (int j = 0; j < M; j++)
+            if (a[i][j] != b[i][j]) return false;
+    return true;
+}
+
+void search(vector<vector<int>> m, vector<vector<int>> &target, int &answer, bool dr, bool dc, bool eq) {
+    int n = 0, r = 0, c = 0;
+    do if (( eq && (m[r][c] != target[r][c])) ||
+           (!eq && (m[r][c] == target[r][c]))) {
+        n++;
+        reverse(m, r, c, !dr, !dc);
+    } while ((r += dr) < N && (c += dc) < M);
+
+    r = 0, c = 0;
+    do if (m[r][c] != target[r][c]) {
+            n++;
+            reverse(m, r, c, dr, dc);
+    } while ((r += !dr) < N && (c += !dc) < M);
+
+    if (equal(m, target) && (answer < 0 || answer > n)) {
+        answer = n;
+    }
+}
+
+int solution(vector<vector<int>> beginning, vector<vector<int>> target) {
+    int answer = -1, n = 0;
+    N = beginning.size(); M = beginning[0].size();
+    search(beginning, target, answer, 0, 1, true);
+    search(beginning, target, answer, 1, 0, true);
+    search(beginning, target, answer, 0, 1, false);
+    search(beginning, target, answer, 1, 0, false);
+    return answer;
+}