[BOJ 15684] 사다리 조작 resolve 2

src/week3/BOJ15684/BOJ15684_V3.cpp

@@ -0,0 +1,53 @@
+#include <bits/stdc++.h>
+using namespace std;
+int N, H, M;
+int visited[31][11];
+int ret = 4;
+bool check() {
+    int start;
+    for (int i=1; i<N; i++) {
+        start = i;
+        for (int j=1; j<=H; j++) {
+            if (visited[j][start]) start++;
+            else if (visited[j][start-1]) start--;
+        }
+        if (start != i) return false;
+    }
+    return true;
+}
+void solve(int here, int cnt) {
+    if (cnt > 3 || cnt >= ret) return;
+
+    if (check()) {
+        ret = min(ret, cnt);
+    }
+    for (int i=here; i<=H; i++) {
+        for (int j=1; j<N; j++) {
+            if (visited[i][j] || visited[i][j+1] || visited[i][j-1]) continue;
+            visited[i][j] = 1;
+            solve(i, cnt+1);
+            visited[i][j] = 0;
+        }
+    }
+}
+int main() {
+
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    cout.tie(NULL);
+
+    cin >> N >> M >> H;
+
+    for (int i=0; i<M; i++) {
+        int y,x;
+        cin >> y >> x;
+        visited[y][x] = 1;
+    }
+
+    solve(1, 0);
+
+    if (ret == 4) cout << -1 << '\n';
+    else cout << ret << '\n';
+
+    return 0;
+}