HDU 5818 Joint Stacks (left-leaning tree)

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Ideas:

The key to the problem is how to merge two stacks, we can use a data structure called left-leaning tree, to satisfy the nature of the heap and the nature of the collection, to support the complexity of O (logn) to delete the top element of the heap, insert an element, merge two of the heap.

See the code for details:

#include <bits/stdc++.h>using namespace Std;typedef pair<int, int> p;const int maxn = 152400;    P v[maxn];int tot, u, A, B, L[MAXN], R[MAXN], d[maxn];//id[x] represents the number of the tree where x is the int Merge (int x, int y) {if (!x) return y;    if (!y) return x;    if (V[x] < v[y]) swap (x, y);    R[X] = Merge (r[x], y);    if (D[l[x]] < d[r[x]]) swap (l[x], r[x]);    D[X] = d[r[x]] + 1; return x;}    int init (P x) {tot++;    V[tot] = x;    L[tot] = R[tot] = D[tot] = 0; return tot;} int Insert (int x, P y) {return Merge (x, init (y));} P Top (int x) {return v[x];} int pop (int x) {return Merge (L[x], r[x]);}    Char op[30], str[30], str2[30];int val;int main () {int kase = 0;    int N;        while (scanf ("%d", &n), N) {memset (V, 0, sizeof (v));        memset (l, 0, sizeof (l));        memset (r, 0, sizeof (r));        memset (d, 0, sizeof (d));        tot = U = A = b = 0;        printf ("Case #%d:\n", ++kase);        int PosA = init (P (-1,-1));        int PosB = init (P (-2,-1)); for (int i = 1; I <= N;            ++i) {scanf ("%s%s", op, str);                if (op[1] = = ' U ') {scanf ("%d", &val);                if (str[0] = = ' A ') {PosA = Insert (PosA, P (i, Val));                } else {PosB = Insert (PosB, P (i, Val));                }} else if (op[1] = = ' O ') {P ans;                    if (str[0] = = ' A ') {ans = top (PosA);                PosA = Pop (PosA);                    } else {ans = top (PosB);                PosB = Pop (PosB);            } printf ("%d\n", Ans.second);                } else if (op[1] = = ' E ') {scanf ("%s", str2);                    if (str[0] = = ' A ') {PosA = Merge (PosA, PosB);                PosB = init (P (-I,-1));                    } else {PosB = Merge (PosA, PosB);                PosA = init (P (-I,-1));  }            }        }    }  return 0;} 

HDU 5818 Joint Stacks (left-leaning tree)