题目链接：
lrj--p155。
1 #include<cstdio> 2 #include<iostream> 3 #include<cstring> 4 #include<string> 5 #include<sstream> 6 using namespace std; 7 const int maxn=10010; 8 int post[maxn],med[maxn],lson[maxn],rson[maxn]; 9 int best,best_sum; 10 11 int build(int l1,int r1,int l2,int r2 ) 12 { 13 if(l1>r1) return 0; 14 int root=post[r2]; 15 int p=l1; 16 while(med[p]!=root) p++; 17 int cnt=p-l1; //左子树 18 lson[root]=build(l1,p-1,l2,l2+cnt-1); 19 rson[root]=build(p+1,r1,l2+cnt,r2-1); 20 return root; 21 } 22 void dfs(int u,int sum) 23 { 24 sum+=u; 25 if(!lson[u]&&!rson[u]) { 26 if(sum<best_sum||sum==best_sum&&u<best) {best=u;best_sum=sum;} 27 28 } 29 30 if(lson[u]) dfs(lson[u],sum); 31 if(rson[u]) dfs(rson[u],sum); 32 } 33 string s1; 34 int main() 35 { 36 while(getline(cin,s1)) 37 { 38 int v; 39 stringstream ss(s1); 40 int c=0; 41 while(ss>>v) med[c++]=v; 42 int len=c; 43 for(int i=0;i<len;i++) 44 cin>>post[i]; 45 build(0,len-1,0,len-1); 46 best_sum=100000000; 47 dfs(post[len-1],0); 48 cout<<best<<" "; 49 getchar(); 50 51 52 } 53 return 0; 54 }