PAT（甲级）2017年秋季考试

PAT（甲级）2017年秋季考试

D题红黑树待补21/30
大佬的代码，看着想哭，这才是艺术啊

A Cut Integer

模拟题

#include
using namespace std;

typedef long long ll;
int n;

int getLen(ll x){
    int len = 0;
    while(x){
        len++;
        x/=10;
    }
    return len;
}

int main(){
    cin>>n;
    while(n--){
        ll x;
        cin>>x;
        int len = getLen(x);
        ll temp = x;
        int t = 0;
        ll right = 0;
        ll rightTemp = 0;
        ll left = 0;
        while(t

B Splitting A Linked List

链表题

#include
using namespace std;

const int maxn = 1010;
const int maxm = 100000;
struct node{
    int address;
    int data;
    int next;
}nod[maxm];

vector vec;
vector ans;
int Head,n,k;
int vis[maxm];

int main(){
    cin>>Head>>n>>k;
    for(int i=1;i<=n;i++){
        int add,dat,nex;
        cin>>add>>dat>>nex;
        nod[add].address = add;
        nod[add].data = dat;
        nod[add].next = nex;
    }
    for(int head = Head;head!=-1;head=nod[head].next){
        vec.push_back(nod[head]);
    }
    for(int i=0;i= 0 && vec[i].data <= k && !vis[vec[i].address]){
            ans.push_back(vec[i]);
            vis[vec[i].address] = 1;
        }
    }
    for(int i=0;i 1) printf("%05d %d -1",ans[ans.size()-1].address,ans[ans.size()-1].data);
    return 0;
}

C Vertex Cover

简单图论，最小覆盖，邻接表存图

#include
using namespace std;

const int maxn = 10000;
int n,m,k;
int g[maxn][maxn];
int vis[maxn][maxn];
vector vec;
void init(){
    for(int i=0;i>n>>m;
    for(int i=0;i>u>>v;
        g[u][v] = 1;
        g[v][u] = 1;
    }
    cin>>k;
    for(int t=0;t>nv;
        for(int i=0;i>d;
            vec.push_back(d);
        }
        for(int i=0;i<=nv-1;i++){
            for(int j=0;j

D Is It A Red-Black Tree

判断是否红黑树 21分/30分 待补

#include
using namespace std;

/*
21分 
*/

const int maxn = 1010;
int k,n;
int pre[maxn];
int rb[maxn];
int xb[maxn];
//bool childFlag = true;
struct node{
    int v;
    int cnt;
    node *l;
    node *r;
};

void insert(node *root,int pos){
    if(root == NULL) return;
    if(rb[pos] == 0){
        root->cnt++;
    }
    if(root->v > pre[pos]){
        if(root->l == NULL){
            root->l = new node();
            root->l->v = pre[pos];
            root->l->l = NULL;
            root->l->r = NULL;
            if(rb[pos] == 0) root->l->cnt = 1;
        }else{
            insert(root->l,pos);
        }
    }else{
        if(root->r == NULL){
            root->r = new node();
            root->r->v = pre[pos];
            root->r->l = NULL;
            root->r->r = NULL;
            if(rb[pos] == 0) root->r->cnt = 1;
        }else{
            insert(root->r,pos);
        }   
    }
}

bool checkChild(node *Root){
    if(Root->l){
        if(rb[Root->v] < 0 && rb[Root->l->v] <0){
            return false;
        }else{
            return checkChild(Root->l);
        }
    }
    if(Root->r){
        if(rb[Root->v] < 0 && rb[Root->r->v] <0){
            return false;
        }else{
            return checkChild(Root->r);
        }
    }
    return true;
}

void init(){
    for(int i=0;i<=n;i++){
        rb[i] = 0;
        xb[i] = 0;
        pre[i] = 0;
    }
}

void bfs(node *root){
    if(root == NULL) return;
    cout<v<<" "<cnt<l) bfs(root->l);
    if(root->r) bfs(root->r);
}

bool can = true;
void travel(node *root){
    if(can == false) return;
    if(root->v == 15){
        int ddd = 1;
    }
    if(root->l && root->r){
        if(root->l->cnt != root->r->cnt) {
            can = false;
            return;
        }
    }
    if(root->l) {
        travel(root->l);
    }
    if(root->r) {
        travel(root->r);
    }
}

int main(){
    cin>>k;
    while(k--){
        cin>>n;
        init();
        for(int i=1;i<=n;i++) {
            int d;
            cin>>d;
            if(d < 0 ){
                xb[-d] = 1;
                rb[i] = 1;
                pre[i] = -d;
            }else{
                rb[i] = 0;
                pre[i] = d;
            }
        }
        node *Root = new node(); 
        Root->l = NULL;
        Root->r = NULL;
        Root->v = pre[1];
        Root->cnt = 1;
        for(int i=2;i<=n;i++) insert(Root,i);
        if(rb[1] == 1) puts("No");
        else if(checkChild(Root) == false) puts("No");
        else{
            //bfs(Root);
            can = true;
            travel(Root);
            if(can == false) puts("No");
            else puts("Yes");
        }
    }
    return 0;
}