2023 rcpc

2023/rcpc/d2/editorial/d-edenland-69.cpp

@@ -0,0 +1,70 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+#define int long long
+
+int n,a[200005],b[200005];
+int spa[200005],spb[200005];
+int nxt[200005];
+int rmq[200005][20];
+int lg[200005];
+int v[200005],spv[200005];
+
+void calc_nxt()
+{
+    ///daca astept la poz i, astept la urmatoarea poz pentru care sum(a[j] de la i + 1 la p) > sum(b[j] de la i la p - 1)
+    ///fie v[j] = a[j] - b[j - 1]
+    ///de la pozitia i, astept la prima pozitie la care suma(v[j] de la i + 1 la p) > 0
+    ///din sume partiale pe p, dupa pozitia i mai astept la prima pozitie cu spv[p] > spv[i]
+    for (int i = 1; i <= n; i++)
+        v[i] = a[i] - b[i - 1];
+    for (int i = 1; i <= n; i++)
+        spv[i] = spv[i - 1] + v[i];
+    spv[n + 1] = 1e18;
+    stack<int>s;
+    s.push(n + 1);
+    for (int i = n; i >= 1; i--)
+    {
+        while (spv[i] >= spv[s.top()])
+            s.pop();
+        nxt[i] = s.top();
+        s.push(i);
+    }
+}
+
+signed main()
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    cout.tie(NULL);
+    cin >> n;
+    for (int i = 1; i <= n; i++)
+        cin >> a[i],spa[i] = a[i] + spa[i - 1];
+    for (int i = 1; i <= n; i++)
+        cin >> b[i],spb[i] = b[i] + spb[i - 1];
+    calc_nxt();
+    for (int i = 0; i <= 19; i++)
+        rmq[n + 1][i] = n + 1;
+    for (int i = 2; i <= n; i++)
+        lg[i] = 1 + lg[i / 2];
+    for (int i = 1; i <= n; i++)
+        rmq[i][0] = nxt[i];
+    for (int j = 1; j <= lg[n]; j++)
+        for (int i = 1; i <= n; i++)
+            rmq[i][j] = rmq[rmq[i][j - 1]][j - 1];
+    int q;
+    cin >> q;
+    for (int i = 1; i <= q; i++)
+    {
+        int l,r;
+        cin >> l >> r;
+        int pos = l;
+        for (int j = lg[n]; j >= 0; j--)
+            if (rmq[pos][j] <= r)
+                pos = rmq[pos][j];
+        int timp = (spb[r] - spb[pos - 1]) - (spa[r] - spa[pos]);
+        cout << timp << '\n';
+    }
+    return 0;
+}