LibreOJ: 3356

「BalticOI 2017 Day1」Toll

.vscode/settings.json

@@ -40,7 +40,7 @@
   "resmon.updatefrequencyms": 500,
   "task.quickOpen.skip": false,
   "terminal.integrated.defaultProfile.windows": "PowerShell",
-  "workbench.colorTheme": "Material Theme Lighter High Contrast",
+  "workbench.colorTheme": "Material Theme Darker High Contrast",
   "workbench.iconTheme": "material-icon-theme",
   "workbench.list.smoothScrolling": true,
   "workbench.settings.openDefaultKeybindings": false,

LibreOJ/3356-2.cpp

@@ -0,0 +1,129 @@
+/**
+ * @file 3356.cpp
+ * @author Macesuted (i@macesuted.moe)
+ * @date 2024-07-10
+ *
+ * @copyright Copyright (c) 2024
+ * @brief
+ *     O(n^(2/3) * q^(2/3) * k^(5/3))
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#ifndef LOCAL
+#define endl '\n'
+#endif
+
+bool mem1;
+
+#define maxn 50005
+#define maxB 1005
+#define maxk 5
+
+typedef pair<int, int> pii;
+
+vector<pii> graph[maxn], rgraph[maxn];
+int bl[maxB], bel[maxn];
+int64_t distL[maxk][maxn], distR[maxk][maxn], dist[maxB][maxB][maxk][maxk], distc[maxn];
+queue<int> que;
+
+void solve(void) {
+    int K, n, m, q;
+    cin >> K >> n >> m >> q;
+    n = n / K + (n % K != 0) - 1;
+    for (int i = 1, x, y, t; i <= m; i++) cin >> x >> y >> t, graph[x].emplace_back(y, t), rgraph[y].emplace_back(x, t);
+
+    auto _ = [&](int x, int y) { return x * K + y; };
+
+    int B = min(n, (int)max({1., n / 1000., pow((double)n * n * K / q, 1. / 3)})), bcnt = 0;
+    bl[0] = 0;
+    while (bl[bcnt] < n) bl[bcnt + 1] = bl[bcnt] + B, bcnt++;
+    if (bl[bcnt] > n) bl[bcnt] = n;
+    for (int i = 0; i < bcnt; i++)
+        for (int j = bl[i]; j < bl[i + 1]; j++) bel[j] = i;
+    bel[n] = bcnt;
+
+    memset(distL, 0x3f, sizeof(distL)), memset(distR, 0x3f, sizeof(distR)), memset(dist, 0x3f, sizeof(dist));
+    for (int i = 0; i < bcnt; i++) {
+        for (int o = 0; o < K; o++) {
+            distL[o][_(bl[i], o)] = 0, que.push(_(bl[i], o));
+            while (!que.empty()) {
+                int p = que.front();
+                que.pop();
+                for (auto [t, v] : graph[p])
+                    if (t < _(bl[i + 1], 0)) {
+                        if (distL[o][t] == 0x3f3f3f3f3f3f3f3f) que.push(t);
+                        distL[o][t] = min(distL[o][t], distL[o][p] + v);
+                    }
+            }
+        }
+        for (int o = 0; o < K; o++) {
+            for (auto [t, v] : rgraph[_(bl[i + 1], o)]) distR[o][t] = v, que.push(t);
+            while (!que.empty()) {
+                int p = que.front();
+                que.pop();
+                for (auto [t, v] : rgraph[p])
+                    if (t >= _(bl[i], 0)) {
+                        if (distR[o][t] == 0x3f3f3f3f3f3f3f3f) que.push(t);
+                        distR[o][t] = min(distR[o][t], distR[o][p] + v);
+                    }
+            }
+        }
+        for (int x = 0; x < K; x++)
+            for (int y = 0; y < K; y++) dist[i][i + 1][x][y] = distR[y][_(bl[i], x)];
+    }
+    for (int i = 0; i < bcnt; i++)
+        for (int j = i + 2; j <= bcnt; j++)
+            for (int x = 0; x < K; x++)
+                for (int y = 0; y < K; y++)
+                    for (int z = 0; z < K; z++)
+                        if (dist[i][j - 1][x][z] != 0x3f3f3f3f3f3f3f3f && dist[j - 1][j][z][y] != 0x3f3f3f3f3f3f3f3f)
+                            dist[i][j][x][y] = min(dist[i][j][x][y], dist[i][j - 1][x][z] + dist[j - 1][j][z][y]);
+    for (int i = 0; i <= bcnt; i++)
+        for (int x = 0; x < K; x++) dist[i][i][x][x] = 0;
+    for (int i = 0; i < K; i++) distL[i][_(n, i)] = 0;
+
+    while (q--) {
+        int a, b;
+        cin >> a >> b;
+        int na = a / K, nb = b / K, bela = bel[na], belb = bel[nb];
+        if (bela == belb) {
+            for (int i = a; i <= b; i++) distc[i] = INT64_MAX;
+            distc[a] = 0;
+            for (int i = a; i <= b; i++)
+                if (distc[i] != INT64_MAX)
+                    for (auto [t, v] : graph[i]) distc[t] = min(distc[t], distc[i] + v);
+            cout << (distc[b] == INT64_MAX ? -1 : distc[b]) << endl;
+            continue;
+        }
+
+        int64_t ans = INT64_MAX;
+        for (int x = 0; x < K; x++)
+            if (distR[x][a] != 0x3f3f3f3f3f3f3f3f)
+                for (int y = 0; y < K; y++)
+                    if (distL[y][b] != 0x3f3f3f3f3f3f3f3f && dist[bela + 1][belb][x][y] != 0x3f3f3f3f3f3f3f3f)
+                        ans = min(ans, distR[x][a] + dist[bela + 1][belb][x][y] + distL[y][b]);
+
+        cout << (ans == INT64_MAX ? -1 : ans) << endl;
+    }
+    return;
+}
+
+bool mem2;
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+#ifdef LOCAL
+    cerr << "Memory Cost: " << abs(&mem1 - &mem2) / 1024. / 1024. << "MB" << endl;
+#endif
+
+    int _ = 1;
+    while (_--) solve();
+
+#ifdef LOCAL
+    cerr << "Time Cost: " << clock() * 1000. / CLOCKS_PER_SEC << "MS" << endl;
+#endif
+    return 0;
+}