P4259 [Code+#3]寻找车位

https://www.luogu.com.cn/record/97050384

Luogu/P4259/P4259.cpp

@@ -0,0 +1,148 @@
+#include <iostream>
+#include <algorithm>
+#include <deque>
+#include <iterator>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 4e6 + 5;
+
+int n, m, q;
+
+template <typename T>
+class array {
+  private:
+    T data[N << 2];
+
+  public:
+    array() {
+        std::fill(std::begin(data), std::end(data), 0);
+    }
+
+    T* operator[](int x) {
+        return data + x * m;
+    }
+};
+
+array<bool> g;
+array<int> up, down, sum;
+
+void pushup(int u, int ls, int rs, int l, int r) {
+    std::deque<int> q1, q2;
+
+    for (int i = 1, j = 1; i <= m; i++) {
+        while (!q1.empty() && down[ls][i] < down[ls][q1.back()]) q1.pop_back();
+        while (!q2.empty() && up[rs][i] < up[rs][q2.back()]) q2.pop_back();
+
+        q1.emplace_back(i);
+        q2.emplace_back(i);
+
+        while (j <= i && i - j + 1 > up[rs][q2.front()] + down[ls][q1.front()]) {
+            j++;
+
+            if (q1.front() < j) q1.pop_front();
+            if (q2.front() < j) q2.pop_front();
+        }
+
+        sum[u][i] = std::max({sum[ls][i], sum[rs][i], i - j + 1});
+    }
+
+    for (int i = 1; i <= m; i++) {
+        up[u][i] = up[ls][i] + (up[ls][i] == l ? up[rs][i] : 0);
+        down[u][i] = down[rs][i] + (down[rs][i] == r ? down[ls][i] : 0);
+    }
+}
+
+void build(int u, int l, int r) {
+    if (l == r) {
+        for (int i = 1; i <= m; i++) {
+            up[u][i] = down[u][i] = sum[u][i] = g[l][i];
+        }
+
+        return;
+    }
+
+    int mid = (l + r) >> 1;
+
+    build(u << 1, l, mid);
+    build(u << 1 | 1, mid + 1, r);
+
+    pushup(u, u << 1, u << 1 | 1, mid - l + 1, r - mid);
+}
+
+void modify(int u, int l, int r, int p, int y) {
+    if (l == r) {
+        up[u][y] = down[u][y] = sum[u][y] = g[p][y] ^= 1;
+
+        return;
+    }
+
+    int mid = (l + r) >> 1;
+
+    if (p <= mid) modify(u << 1, l, mid, p, y);
+    else modify(u << 1 | 1, mid + 1, r, p, y);
+
+    pushup(u, u << 1, u << 1 | 1, mid - l + 1, r - mid);
+}
+
+void query(int u, int l, int r, int ql, int qr) {
+    if (ql <= l && r <= qr) {
+        pushup(0, 0, u, l - ql, r - l + 1);
+
+        return;
+    }
+
+    int mid = (l + r) >> 1;
+
+    if (ql <= mid) query(u << 1, l, mid, ql, qr);
+    if (qr > mid) query(u << 1 | 1, mid + 1, r, ql, qr);
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> m >> q;
+
+    for (int i = 1; i <= n; i++) {
+        for (int j = 1; j <= m; j++) {
+            cin >> g[i][j];
+        }
+    }
+
+    build(1, 1, n);
+
+    while (q--) {
+        int op;
+
+        cin >> op;
+
+        if (op == 0) {
+            int x, y;
+
+            cin >> x >> y;
+
+            modify(1, 1, n, x, y);
+        } else {  // op == 1
+            int l, s, r, t, ans = 0;
+
+            cin >> l >> s >> r >> t;
+
+            for (int i = 1; i <= m; i++) {
+                up[0][i] = down[0][i] = sum[0][i] = 0;
+            }
+
+            query(1, 1, n, l, r);
+
+            for (int i = s; i <= t; i++) {
+                ans = std::max(ans, std::min(sum[0][i], i - s + 1));
+            }
+
+            cout << ans << endl;
+        }
+    }
+
+    return 0;
+}