P2254 [NOI2005] 瑰丽华尔兹

https://www.luogu.com.cn/record/77598294

Luogu/P2254/P2254.cpp

@@ -0,0 +1,108 @@
+#include <iostream>
+#include <deque>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 205;
+
+int n, m, x, y, k, s, t, d, f[N][N], ans;
+bool g[N][N];
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> m >> x >> y >> k;
+
+    for (int i = 1; i <= n; i++) {
+        for (int j = 1; j <= m; j++) {
+            char c;
+            cin >> c;
+            g[i][j] = c == 'x';
+            f[i][j] = -0x3f3f3f3f;
+        }
+    }
+
+    f[x][y] = 0;
+    for (int i = 1; i <= k; i++) {
+        cin >> s >> t >> d;
+
+        int len = t - s + 1;
+        switch (d) {
+            case 1: {  // 上
+                for (int y = 1; y <= m; y++) {
+                    std::deque<std::pair<int, int>> q;
+                    for (int j = 1, x = n; x; j++, x--) {
+                        if (g[x][y]) {
+                            q.clear();
+                        } else {
+                            while (!q.empty() && q.back().second < f[x][y] - j) q.pop_back();
+                            q.push_back(std::make_pair(j, f[x][y] - j));
+                            while (!q.empty() && j - q.front().first > len) q.pop_front();
+                            f[x][y] = q.front().second + j;
+                            ans = std::max(ans, f[x][y]);
+                        }
+                    }
+                }
+                break;
+            }
+            case 2: {  // 下
+                for (int y = 1; y <= m; y++) {
+                    std::deque<std::pair<int, int>> q;
+                    for (int j = 1, x = 1; x <= n; j++, x++) {
+                        if (g[x][y]) {
+                            q.clear();
+                        } else {
+                            while (!q.empty() && q.back().second < f[x][y] - j) q.pop_back();
+                            q.push_back(std::make_pair(j, f[x][y] - j));
+                            while (!q.empty() && j - q.front().first > len) q.pop_front();
+                            f[x][y] = q.front().second + j;
+                            ans = std::max(ans, f[x][y]);
+                        }
+                    }
+                }
+                break;
+            }
+            case 3: {  // 左
+                for (int x = 1; x <= n; x++) {
+                    std::deque<std::pair<int, int>> q;
+                    for (int j = 1, y = m; y; j++, y--) {
+                        if (g[x][y]) {
+                            q.clear();
+                        } else {
+                            while (!q.empty() && q.back().second < f[x][y] - j) q.pop_back();
+                            q.push_back(std::make_pair(j, f[x][y] - j));
+                            while (!q.empty() && j - q.front().first > len) q.pop_front();
+                            f[x][y] = q.front().second + j;
+                            ans = std::max(ans, f[x][y]);
+                        }
+                    }
+                }
+                break;
+            }
+            case 4: {  // 右
+                for (int x = 1; x <= n; x++) {
+                    std::deque<std::pair<int, int>> q;
+                    for (int j = 1, y = 1; y <= m; j++, y++) {
+                        if (g[x][y]) {
+                            q.clear();
+                        } else {
+                            while (!q.empty() && q.back().second < f[x][y] - j) q.pop_back();
+                            q.push_back(std::make_pair(j, f[x][y] - j));
+                            while (!q.empty() && j - q.front().first > len) q.pop_front();
+                            f[x][y] = q.front().second + j;
+                            ans = std::max(ans, f[x][y]);
+                        }
+                    }
+                }
+                break;
+            }
+        }
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}