#895. 「雅礼集训 2018 Day1」养花（flower）

https://sjzezoj.com/submission/58169

S2OJ/895/895.cpp

@@ -0,0 +1,93 @@
+#include <iostream>
+#include <algorithm>
+#include <cmath>
+#include <set>
+#include <tuple>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e5 + 5,
+          M = 505;
+
+int n, m, a[N];
+std::tuple<int, int, int> q[N];
+int b, t, st[M], ed[M], pos[N], max[M][N];
+int tmp[N];
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> m;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+    }
+
+    for (b = 1, t = std::sqrt(n);; b++) {
+        st[b] = (b - 1) * t + 1;
+        ed[b] = std::min(n, b * t);
+
+        if (b * t >= n) break;
+    }
+
+    for (int i = 1; i <= b; i++) {
+        for (int j = st[i]; j <= ed[i]; j++) {
+            pos[j] = i;
+        }
+    }
+
+    for (int i = 1; i <= m; i++) {
+        cin >> std::get<0>(q[i]) >> std::get<1>(q[i]) >> std::get<2>(q[i]);
+    }
+
+    int max_k = std::get<2>(*std::max_element(q + 1, q + 1 + m, [&](auto a, auto b) -> bool { return std::get<2>(a) < std::get<2>(b); }));
+
+    for (int i = 1; i <= b; i++) {
+        std::fill_n(tmp, N, 0);
+
+        for (int j = st[i]; j <= ed[i]; j++) {
+            tmp[a[j]] = a[j];
+        }
+
+        for (int j = 1; j <= 100000; j++) {
+            tmp[j] = std::max(tmp[j], tmp[j - 1]);
+        }
+
+        for (int j = 1; j <= max_k; j++) {
+            for (int k = 0; k <= max_k; k += j) {
+                max[i][j] = std::max(max[i][j], tmp[std::min(j + k - 1, 100000)] - k);
+            }
+        }
+    }
+
+    for (int i = 1; i <= m; i++) {
+        int l, r, k, res = 0;
+
+        std::tie(l, r, k) = q[i];
+
+        if (pos[l] == pos[r]) {
+            for (int j = l; j <= r; j++) {
+                res = std::max(res, a[j] % k);
+            }
+        } else {
+            for (int j = l; j <= ed[pos[l]]; j++) {
+                res = std::max(res, a[j] % k);
+            }
+
+            for (int j = pos[l] + 1; j <= pos[r] - 1; j++) {
+                res = std::max(res, max[j][k]);
+            }
+
+            for (int j = st[pos[r]]; j <= r; j++) {
+                res = std::max(res, a[j] % k);
+            }
+        }
+
+        cout << res << endl;
+    }
+
+    return 0;
+}