【哈夫曼樹】POJ 3253

#include <map>#include <set>#include <list>#include <queue>#include <deque>#include <stack>#include <string>#include <time.h>#include <cstdio>#include <math.h>#include <iomanip>#include <cstdlib>#include <limits.h>#include <string.h>#include <iostream>#include <fstream>#include <algorithm>using namespace std;#define LL long long#define MIN INT_MIN#define MAX INT_MAX#define PI acos(-1.0)#define FRE freopen("input.txt","r",stdin)#define FF freopen("output.txt","w",stdout)#define N 20005priority_queue<LL,vector<LL>,greater<LL> > pp;int main () {    int n;    while (scanf("%d",&n) != -1) {        int i;        while (!pp.empty()) pp.pop();        LL d;        LL ans = 0;        for (i = 0; i < n; i++) {            scanf("%I64d",&d);            pp.push(d);        }        while (pp.size() != 1) {            LL a,b;            a = pp.top();            pp.pop();            b = pp.top();            pp.pop();            ans += (a + b);            pp.push(a + b);        }        if (n == 1) {            printf("%I64d\n",d);            continue;        }        printf("%I64d\n",ans);    }    return 0;}