PTA 1140 1141 1142 1143

1140 Look-and-say Sequence

思路:模拟

#include
using namespace std;

typedef long long ll;
int d,n;
const int maxn = 10010;
int cnt[11];
vector a;
vector b;

int main(){
    scanf("%d%d",&d,&n);
    a.push_back(d); 
    if(n == 1) {
        printf("%lld",d);
        return 0;
    }
    for(int i=2;i<=n;i++){
        int j = 0;
        b.clear();
        int len = a.size();
        while(j < len){
            int curv = a[j];
            int cnt = 0;
            while(j

1141 PAT Ranking of Institutions

思路:结构体排序,map统计查询

#include
#include
#include
using namespace std;

int n;
const int maxn = 1e5+10;
struct node{
    string id;
    double score;
    string cap;
};

struct node stu[maxn];
map mp;
map scores;

struct capNode{
    string cap;
    int score;
    int nums;
    capNode(string ss,double cc,int num){
        cap = ss;
        score = cc;
        nums = num;
    }
};

vector vec;

bool cmp(capNode x,capNode y){
    if(x.score == y.score) {
        if(x.nums == y.nums) return x.cap < y.cap;
        return x.nums < y.nums;
    }
    return x.score > y.score;
}

int main(){
    scanf("%d",&n);
    for(int i=1;i<=n;i++){
        string curCap;
        cin>>stu[i].id>>stu[i].score>>curCap;
        transform(curCap.begin(),curCap.end(),curCap.begin(),::tolower);
        stu[i].cap = curCap;
        mp[stu[i].cap]++;
        if(stu[i].id[0] == 'T'){
            scores[stu[i].cap] += stu[i].score*1.5;
        }else if(stu[i].id[0] == 'A'){
            scores[stu[i].cap] += stu[i].score;
        }else{
            scores[stu[i].cap] += stu[i].score*1.0/1.5;
        }
    }
    map::iterator it = mp.begin();
    while(it!=mp.end()){
        string name = it->first;
        int num = it->second;
        int sc = (int)scores[name];
        vec.push_back(capNode(name,sc,num));
        it++;
    }
    sort(vec.begin(),vec.end(),cmp);
    int len = vec.size();
    printf("%d\n",len);
    if(len > 0){
        int lastScore = vec[0].score;
        int rank = 1;
        for(int i=0;i

1142 Maximal Clique

思路:图论,判断是否同一“集合”,按题目要求判断是否有边

#include
using namespace std;

const int maxn = 210;
int n,ne;
int m;
int g[maxn][maxn];
int a[maxn];
int vis[maxn];
int k;

bool isClique(){
    for(int i=1;i<=k;i++){
        for(int j=1;j<=k;j++){
            if(i!=j && g[a[i]][a[j]] == 0) return false;
        }
    }
    return true;
}

bool isMaxClique(){
    for(int i=1;i<=n;i++) vis[i] = 0;
    for(int i=1;i<=k;i++) vis[a[i]] = 1;
    for(int i=1;i<=n;i++){
        if(!vis[i]){
            for(int p=1;p<=k;p++){
                for(int q=1;q<=k;q++){
                    if(p != q || (k==1)){ //这里特判k==1的情况  如样例图中查询1 8:8号结点应该输出Not Maximal 
                        if(g[i][a[p]]==1 && g[i][a[q]] == 1){
                            return false;
                        }
                    }
                }
            }
        }
    }
    return true;
}

int main(){
    scanf("%d%d",&n,&ne);
    for(int i=1;i<=ne;i++){
        int u,v;
        scanf("%d%d",&u,&v);
        g[u][v] = g[v][u] = 1;
    }
    scanf("%d",&m);
    for(int i=1;i<=m;i++){
        scanf("%d",&k);
        for(int j=1;j<=k;j++) scanf("%d",&a[j]);
        bool flag1 = isClique(); 
        bool flag2 = isMaxClique();
        if(flag1 == false){
            puts("Not a Clique");
        }else{
            if(flag2 == false){
                puts("Not Maximal");
            }else{
                puts("Yes");
            }
        }
    }
    return 0;
} 

1143 Lowest Common Ancestor 29/30

思路:给先序序列建树,找最近公共祖先
一个点段错误,有时间再补。。
PTA 1140 1141 1142 1143_第1张图片

#include
using namespace std;

const int maxn = 10010;
int m,n;
struct node{
    int v;
    node *l;
    node *r;
};
int a[maxn];
set se;
int deep[maxn];
int fa[maxn];

void getDeep(node *root,int depth,int father){
    if(root == NULL) return;
    deep[root->v] = depth;
    fa[root->v] = father;
    if(root->l != NULL) getDeep(root->l,depth+1,root->v);
    if(root->r != NULL) getDeep(root->r,depth+1,root->v);
}

void build(int pos,node *root){
    if(root == NULL) return;
    node* fa = root;
    int v = a[pos];
    if(v < fa->v){
        if(fa->l == NULL){
            node *cur = new node();
            cur->v = v;
            cur->l = NULL;
            cur->r = NULL;
            fa->l = cur;
            return;
        }
        build(pos,fa->l);
    }else{
        if(fa->r == NULL){
            node *cur = new node();
            cur->v = v;
            cur->l = NULL;
            cur->r = NULL;
            fa->r = cur;
            return;
        }
        build(pos,fa->r);
    }
    return;
}

int main(){
    scanf("%d%d",&m,&n);
    for(int i=1;i<=n;i++) {
        scanf("%d",&a[i]);
        se.insert(a[i]);
    }
    node *Root = new node();
    Root->l = NULL;
    Root->r = NULL;
    if(n>=1) Root->v = a[1];
    else Root->v = 0; 
    if(n>=2) for(int i=2;i<=n;i++) build(i,Root);
    getDeep(Root,1,0);
    for(int i=1;i<=m;i++){
        int u,v;
        scanf("%d%d",&u,&v);
        bool visu = true;
        bool visv = true;
        if(se.find(u) == se.end()) visu = false;
        if(se.find(v) == se.end()) visv = false;
        if(visu == false || visv == false){
            if(visu==false && visv==false) printf("ERROR: %d and %d are not found.\n",u,v);
            else if(visu == false) printf("ERROR: %d is not found.\n",u);
            else printf("ERROR: %d is not found.\n",v);
        }else{
            if(deep[u] < deep[v]){
                int p = u;
                int q = v;
                while(deep[q] > deep[p]) q = fa[q];
                if(q == p) printf("%d is an ancestor of %d.\n",u,v);
                else{
                    while(p != q){
                        p = fa[p];
                        q = fa[q];
                    }
                    printf("LCA of %d and %d is %d.\n",u,v,p);
                }
            }else{
                int p = u;
                int q = v;
                while(deep[p] > deep[q]) p = fa[p];
                if(p == q) printf("%d is an ancestor of %d.\n",v,u);
                else{
                    while(p != q){
                        p = fa[p];
                        q = fa[q];
                    }
                    printf("LCA of %d and %d is %d.\n",u,v,p);
                }
            }
        }
    }
    return 0;
} 

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