[Violence] vijos p1897 xuejie eats steak

Judge heap: recursively determine whether each node's child is larger (smaller) than its father ).

Determine whether BST is ordered by the middle-order traversal.

 1 #include<cstdio> 2 using namespace std; 3 #define lc (rt<<1) 4 #define rc (rt<<1|1) 5 int T,n,a[1001],b[1001],en; 6 void Mid(int rt) 7 { 8     if(lc<=n) Mid(lc); 9     b[++en]=a[rt];10     if(rc<=n) Mid(rc);11 }12 bool is_BST()13 {14     bool f1=1,f2=1; en=0; Mid(1);15     for(int i=2;i<=n;i++) if(b[i]<b[i-1]) {f1=0; break;}16     if(f1) return 1;17     for(int i=2;i<=n;i++) if(b[i]>b[i-1]) {f2=0; break;}18     if(f2) return 1;19     return 0;20 }21 bool is_Heap(int rt)22 {23     if(lc<=n)24       {25           if(a[lc]>a[rt]) return 0;26           if(!is_Heap(lc)) return 0;27       }28     if(rc<=n)29       {30           if(a[rc]>a[rt]) return 0;31           if(!is_Heap(rc)) return 0;32       }33     return 1;34 }35 bool is_Heap_2(int rt)36 {37     if(lc<=n)38       {39           if(a[lc]<a[rt]) return 0;40           if(!is_Heap_2(lc)) return 0;41       }42     if(rc<=n)43       {44           if(a[rc]<a[rt]) return 0;45           if(!is_Heap_2(rc)) return 0;46       }47     return 1;48 }49 int main()50 {51     scanf("%d",&T);52     for(int i=1;i<=T;i++)53       {54           printf("Case #%d: ",i);55           scanf("%d",&n);56           for(int j=1;j<=n;j++) scanf("%d",&a[j]);57           bool flag1=0,flag2=0;58           if(is_BST()) flag1=1;59           if(is_Heap(1)) flag2=1;60           if((!flag2)) if(is_Heap_2(1)) flag2=1;61           if(flag1&&flag2) puts("Both");62           else if(flag1) puts("BST");63           else if(flag2) puts("Heap");64           else puts("Neither");65       }66     return 0;67 }

 

[Violence] vijos p1897 xuejie eats steak