poj 3253 最小堆 优先队列 哈夫曼树

import java.io.*;class Heap {private final int maxn = 50010;int[] data;int r;Heap() {data = new int[maxn];r = 0;}public int size() {return r;}void swap(int a, int b) {int tmp = data[a];data[a] = data[b];data[b] = tmp;}void up(int p) {if (!(p > 0))return;int q = p >> 1;if (data[p] < data[q]) {swap(p, q);up(q);}}void down(int p) {int q;if ((p << 1) >= r)return;else if ((p << 1) == r - 1) {q = p << 1;} else {q = (data[p << 1] < data[p << 1 | 1] ? p << 1 : p << 1 | 1);}if (data[p] > data[q]) {swap(p, q);down(q);}}void push(int n) {data[r++] = n;up(r - 1);}int pop() {int res = data[0];swap(0, r - 1);r--;down(0);return res;}int top() {return data[0];}}public class Main {private static long solve(int[] a) {Heap hp = new Heap();int n = a[0], l1, l2;long res = 0;for (int i = 1; i <= n; i++)hp.push(a[i]);// hp.print();while (hp.size() > 1) {l1 = hp.pop();l2 = hp.pop();res += (long) (l1 + l2);hp.push(l1 + l2);}return res;}public static void main(String[] args) throws IOException {StreamTokenizer in = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));PrintWriter out = new PrintWriter(System.out);while (in.nextToken() != StreamTokenizer.TT_EOF) {int n = (int) in.nval;int[] a = new int[n + 1];a[0] = n;for (int i = 1; i <= n; i++) {in.nextToken();a[i] = (int) in.nval;}if (n > 1)out.println(solve(a));elseout.println(a[1]);out.flush();}out.close();}}