new file: P1081.cpp

P1081.cpp

@@ -0,0 +1,181 @@
+#include <cstdio>
+#include <cmath>
+#include <set>
+#include <map>
+using namespace std;
+const int maxn = 1e5 + 10;
+const int max2 = 20;
+const int inf = 2e9 + 5;
+struct nextp
+{
+    int a, b;
+} np[maxn];
+int n, h[maxn], x0, m;
+int f[max2][maxn][2];
+long long da[max2][maxn][2], db[max2][maxn][2];
+/*
+np(i).a/.b 从i出发的下一个点的编号
+f(i, j, k) k(0/1) 先走 从 j 出发 经过 2^i 天
+da A行驶距离
+db B行驶距离
+*/
+void init_nextp()
+{
+    set<pair<int, int>> nu;
+    nu.insert({inf, n});
+    nu.insert({inf - 1, n});
+    nu.insert({-inf, n});
+    nu.insert({-inf + 1, n});
+    for (int j = n - 1; j >= 0; --j)
+    {
+        auto t = nu.lower_bound({h[j], j});
+        t++;
+        pair<int, int> ans[5];
+        for (int i = 4; i > 0; --i)
+        {
+            ans[i] = *t;
+            t--;
+        }
+        int m1 = inf, m2 = inf, mp1 = 0, mp2 = 0;
+        for (int i = 1; i <= 4; ++i)
+        {
+            int d = abs(ans[i].first - h[j]);
+            if (d < m1)
+            {
+                m2 = m1;
+                mp2 = mp1;
+                m1 = d;
+                mp1 = ans[i].second;
+            }
+            else if (d < m2)
+            {
+                m2 = d;
+                mp2 = ans[i].second;
+            }
+        }
+        np[j].a = mp2;
+        np[j].b = mp1;
+        nu.insert({h[j], j});
+    }
+    return;
+}
+void init_f()
+{
+    for (int j = 0; j < n; ++j)
+    {
+        f[0][j][0] = np[j].a, f[0][j][1] = np[j].b;
+    }
+    f[0][n][0] = f[0][n][1] = n;
+    for (int i = 1; i < max2; ++i)
+        for (int j = 0; j <= n; ++j)
+            for (int k = 0; k < 2; ++k)
+            {
+                int mid = f[i - 1][j][k];
+                if (mid >= n)
+                    f[i][j][k] = n;
+                else
+                    f[i][j][k] = f[i - 1][mid][(i == 1) ? (k ^ 1) : k];
+            }
+    return;
+}
+void init_d()
+{
+    for (int j = 0; j < n; ++j)
+    {
+        da[0][j][0] = (np[j].a < n) ? abs(h[j] - h[np[j].a]) : 0;
+        db[0][j][0] = 0;
+        da[0][j][1] = 0;
+        db[0][j][1] = (np[j].b < n) ? abs(h[j] - h[np[j].b]) : 0;
+    }
+    da[0][n][0] = da[0][n][1] = db[0][n][0] = db[0][n][1] = 0;
+    for (int i = 1; i < max2; ++i)
+        for (int j = 0; j <= n; ++j)
+            for (int k = 0; k < 2; ++k)
+            {
+                int mid = f[i - 1][j][k];
+                if (mid >= n)
+                {
+                    da[i][j][k] = 0;
+                    db[i][j][k] = 0;
+                }
+                else
+                {
+                    int nk = (i == 1) ? (k ^ 1) : k;
+                    da[i][j][k] = da[i - 1][j][k] + da[i - 1][mid][nk];
+                    db[i][j][k] = db[i - 1][j][k] + db[i - 1][mid][nk];
+                }
+            }
+    return;
+}
+void query(int s, int x, long long &la, long long &lb)
+{
+    la = 0;
+    lb = 0;
+    int cur = s;
+    for (int k = max2 - 1; k >= 1; --k)
+    {
+        if (f[k][cur][0] < n && la + lb + da[k][cur][0] + db[k][cur][0] <= x)
+        {
+            la += da[k][cur][0];
+            lb += db[k][cur][0];
+            cur = f[k][cur][0];
+        }
+    }
+    if (f[0][cur][0] < n && la + lb + da[0][cur][0] + db[0][cur][0] <= x)
+    {
+        la += da[0][cur][0];
+        lb += db[0][cur][0];
+    }
+}
+int main()
+{
+    // freopen("drive.in", "r", stdin);
+    // freopen("drive.out", "w", stdout);
+    scanf("%d", &n);
+    for (int i = 0; i < n; ++i)
+    {
+        scanf("%d", &h[i]);
+    }
+    init_nextp();
+    init_f();
+    init_d();
+    scanf("%d", &x0);
+    long long best_a = 0, best_b = 1;
+    int mp = -1;
+    bool all_zero = true;
+    for (int j = 0; j < n; ++j)
+    {
+        long long la, lb;
+        query(j, x0, la, lb);
+        if (lb > 0)
+        {
+            all_zero = false;
+            if (mp < 0 || la * best_b < best_a * lb || (la * best_b == best_a * lb && h[j] > h[mp]))
+            {
+                best_a = la;
+                best_b = lb;
+                mp = j;
+            }
+        }
+    }
+    if (all_zero)
+    {
+        mp = 0;
+        for (int j = 1; j < n; ++j)
+        {
+            if (h[j] > h[mp])
+                mp = j;
+        }
+    }
+    printf("%d\n", mp + 1);
+    scanf("%d", &m);
+    while (m--)
+    {
+        int s, x;
+        scanf("%d %d", &s, &x);
+        long long la, lb;
+        query(s - 1, x, la, lb);
+        printf("%lld %lld\n", la, lb);
+    }
+    return 0;
+}