每次合并选最短的两块木板，用优先队列优化。
//#pragma comment(linker, "/STACK:1024000000,1024000000") #include<cstdio> #include<cstring> #include<cstdlib> #include<algorithm> #include<iostream> #include<sstream> #include<cmath> #include<climits> #include<string> #include<map> #include<queue> #include<vector> #include<stack> #include<set> using namespace std; typedef long long ll; typedef unsigned long long ull; typedef pair<int,int> pii; #define pb(a) push(a) #define INF 0x1f1f1f1f #define lson idx<<1,l,mid #define rson idx<<1|1,mid+1,r #define PI 3.1415926535898 template<class T> T min(const T& a,const T& b,const T& c) { return min(min(a,b),min(a,c)); } template<class T> T max(const T& a,const T& b,const T& c) { return max(max(a,b),max(a,c)); } void debug() { #ifdef ONLINE_JUDGE #else freopen("in.txt","r",stdin); //freopen("d:\out1.txt","w",stdout); #endif } int getch() { int ch; while((ch=getchar())!=EOF) { if(ch!=' '&&ch!=' ')return ch; } return EOF; } int main() { int n; while(scanf("%d",&n)!=EOF) { priority_queue<int,vector<int>,greater<int> > q; for(int i=1;i<=n;i++) { int x; scanf("%d",&x); q.push(x); } long long res=0; for(int i=1;i<n;i++) { int a=q.top();q.pop(); int b=q.top();q.pop(); res=res+a+b; q.push(a+b); } printf("%I64d ",res); } return 0; }