jobdu

1367.cpp

@@ -0,0 +1,51 @@
+/*
+递归验证某数组是否为BST的后序遍历 需要注意的是当一棵树的节点数<=3时 无论顺序为何 都肯定是BST
+*/
+#include <cstdio>
+using namespace std;
+const int MAX=10005;
+int a[MAX];
+
+bool ifPost(int low, int up)
+{
+ bool ret=true;
+ int i,idx=up-1;
+ if(up-low>2)
+ {
+ for (i=low;i<up;++i)
+ {
+ if(a[i]>a[up])
+ {
+ idx=i;
+ break;
+ }
+ }
+ for (i=i+1;i<up;++i)
+ {
+ if (a[i]<a[up])
+ {
+ ret=false;
+ break;
+ }
+ }
+ if(ret)
+ ret=ifPost(low,idx-1)&&ifPost(idx,up-1);
+ }
+ return ret;
+}
+
+int main()
+{
+ int n;
+ while (scanf("%d",&n)!=EOF)
+ {
+ for (int i=0;i<n;++i) 
+ scanf("%d",&a[i]); 
+ bool ans=ifPost(0, n-1);
+ if(ans)
+ printf("Yes\n");
+ else
+ printf("No\n");
+ } 
+ return 0;
+}

1368.cpp

@@ -0,0 +1,53 @@
+/*
+类似于pat1053 比它还简单...
+*/
+#include <cstdio>
+#include <vector>
+using namespace std;
+const int MAX=10005;
+int w[MAX];
+int a[MAX][2];
+
+void findWay(int node, int weight, vector<int> v)
+{
+ weight-=w[node];
+ v.push_back(node);
+ int left=a[node][0], right=a[node][1];
+ if (weight==0&&left==-1&&right==-1)
+ {
+ printf("A path is found:");
+ for(int i=0;i<v.size();++i)
+ printf(" %d",v[i]);
+ printf("\n");
+ } 
+ else
+ {
+ if (left!=-1&&weight>0) 
+ findWay(left,weight,v);
+ if (right!=-1&&weight>0) 
+ findWay(right,weight,v);
+ }
+}
+
+int main()
+{
+ int n,k,tmp;
+ while (scanf("%d%d",&n,&k)!=EOF)
+ {
+ for(int i=1;i<=n;++i)
+ {
+ scanf("%d%d%d",&w[i],&a[i][0],&a[i][1]);
+ //题目中没说是BST 为了字典序输出要把小的放前 而且因为没有路径用-1表示 因此要验证两个都>0
+ if (a[i][0]>0&&a[i][1]>0&&a[i][0]>a[i][1])
+ {
+ tmp=a[i][0];
+ a[i][0]=a[i][1];
+ a[i][1]=tmp;
+ }
+ }
+ vector<int> v;
+ printf("result:\n");
+ findWay(1,k,v);
+ }
+ return 0;
+}