pat advanced level 02-20

Posted 2021-03-08 wifepi

1020 Tree Traversals (25分) ps:tmp定义在函数里过了，定在函数外面错了，人给整傻了

#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 10 ;
int post[maxn], in[maxn], level[maxn] ;
int n ;
void DFS(int root, int st, int ed, int index)
{
    if(st > ed) return ;
    level[index] = post[root] ;
    int tmp = st ;
    while(st < ed && in[tmp] != post[root]) ++ tmp ;
    DFS(root - 1 - ed + tmp, st, tmp - 1, index*2+1) ;
    DFS(root - 1, tmp + 1, ed, index*2+2) ;
}
int main(int argc, char const *argv[])
{
    scanf("%d",&n) ;
    for(int i = 0 ; i < n ; ++ i) scanf("%d",&post[i]) ;
    for(int i = 0 ; i < n ; ++ i) scanf("%d",&in[i]) ;
    memset(level,-1,sizeof level) ;
    DFS(n-1,0,n-1,0) ;
    for(int i = 0, cnt = 1 ; i < maxn ; ++ i) if(level[i] != -1) {printf("%d%c",level[i]," 
"[cnt == n]) ; ++ cnt ; if(cnt > n) break ;}
    return 0;
}

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1021 Deepest Root (25分) 找直径

#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e4 + 10 ;
int n, MAX = -1, ans = 0 ;
int fa[maxn], deep[maxn] ;
vector<int> v[maxn] ;
int Find(int x) {return fa[x] == x ? x : fa[x] = Find(fa[x]) ;}
void merge(int x, int y) {int fx = Find(x), fy = Find(y) ; if(fx != fy) fa[fx] = fy ;}
void BFS(int x)
{
    queue<int> q ; MAX = -1 ;
    while(!q.empty()) q.pop() ;
    for(int i = 1 ; i <= n ; ++ i) deep[i] = -1 ;
    deep[x] = 1 ;
    q.push(x) ;
    while(!q.empty())
    {
        int tmp = q.front() ; q.pop() ;
        for(int i = 0 ; i < v[tmp].size() ; ++ i)
            if(deep[v[tmp][i]] == -1)
            deep[v[tmp][i]] = deep[tmp] + 1, q.push(v[tmp][i]), MAX = max(MAX, deep[tmp]+1) ;
    }
}
int main(int argc, char const *argv[])
{
    set<int> s ; s.clear() ;
    scanf("%d",&n) ;
    for(int i = 1 ; i <= n ; ++ i) fa[i] = i, v[i].clear() ; ans = 0 ;
    for(int i = 1, x, y ; i < n ; ++ i) scanf("%d %d",&x,&y), merge(x,y), v[x].push_back(y), v[y].push_back(x) ;
    for(int i = 1 ; i <= n ; ++ i) if(fa[i] == i) ++ ans ;
    if(ans > 1) {printf("Error: %d components
",ans) ; return 0 ;}
    BFS(1) ;
    for(int i = 1 ; i <= n ; ++ i) if(deep[i] == MAX) s.insert(i) ;
    BFS(*s.begin()) ;
    for(int i = 1 ; i <= n ; ++ i) if(deep[i] == MAX) s.insert(i) ;
    set<int> :: iterator iter = s.begin() ;
    for( ; iter != s.end() ; ++ iter) printf("%d
",*iter) ;
    return 0;
}

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1023 Have Fun with Numbers (20分) 字符串处理

#include <bits/stdc++.h>
using namespace std;
char arr[25], brr[25] ;
int arr1[25], brr1[25], cnt1[15], cnt2[15] ;
int main(int argc, char const *argv[])
{
    scanf("%s",arr) ; int n = strlen(arr) ;
    for(int i = 0 ; i <= 9 ; ++ i) cnt1[i] = cnt2[i] = 0 ;
    for(int i = 0 ; i < n ; ++ i) arr1[n - i - 1] = arr[i] - ‘0‘, cnt1[arr[i]-‘0‘] ++ ;
    int jin = 0 ;
    for(int i = 0 ; i < n ; ++ i)
    {
        brr1[i] = (arr1[i] * 2 + jin) % 10 ;
        if(arr1[i] * 2 + jin > 9) jin = 1 ;
        else jin = 0 ;
    }
    if(jin) brr1[n ++] = 1 ;
    for(int i = 0 ; i < n ; ++ i) cnt2[brr1[i]] ++ ;
    for(int i = 0 ; i < n ; ++ i) brr[n - i - 1] = brr1[i] + ‘0‘ ;
    for(int i = 0 ; i <= 9 ; ++ i) if(cnt1[i] != cnt2[i]) {printf("No
%s
",brr) ; return 0 ;}
    printf("Yes
%s
",brr) ;
    return 0;
}

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1024 Palindromic Number (25分) 字符串处理

#include <bits/stdc++.h>
using namespace std;
const int maxn = 110 ;
char arr[maxn], brr[maxn] ;
int arr1[maxn], brr1[maxn], tmp[maxn] ;
int n, k, cnt = 1, jin = 0 ;
bool check()
{
    for(int i = 0 ; i < n ; ++ i) if(arr[i] != arr[n - i - 1]) return false ;
    return true ;
}
void solve()
{
    for(int i = 0 ; i < n ; ++ i) arr1[n - i - 1] = arr[i] - ‘0‘, brr1[i] = arr[i] - ‘0‘ ; jin = 0 ;
    for(int i = 0 ; i < n ; ++ i) tmp[i] = (arr1[i] + brr1[i] + jin) % 10, jin = (arr1[i] + brr1[i] + jin) / 10 ;
    if(jin) tmp[n ++] = jin, jin = 0 ;
    for(int i = 0 ; i < n ; ++ i) arr[n - i - 1] = tmp[i] + ‘0‘ ;
}
int main(int argc, char const *argv[])
{
    scanf("%s %d",arr,&k) ; n = strlen(arr) ; cnt = 0 ;
    for(int i = 0; i < n ; ++ i) arr1[n - i - 1] = arr[i] - ‘0‘ ;
    while(cnt < k)
    {
        if(check()) {printf("%s
%d
",arr,cnt) ; return 0 ;}
        else solve(), cnt ++ ;
    }
    printf("%s
%d
",arr,k) ;
    return 0;
}

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1025 PAT Ranking (25分) 排序

#include <bits/stdc++.h>
using namespace std;
struct Student
{
    char name[20] ;
    int score, location_number, local_rank, final_rank ;
    bool operator < (const Student & x) const
    {
        if(score != x.score) return score > x.score ;
        return strcmp(name,x.name) < 0 ;
    }
}st[110][310], student[30030] ;
int n, k, cnt = 0 ;
int main(int argc, char const *argv[])
{
    scanf("%d",&n) ; cnt = 0 ;
    for(int j = 1 ; j <= n ; ++ j)
    {
        scanf("%d",&k) ;
        for(int i = 0 ; i < k ; ++ i) scanf("%s %d",st[j][i].name,&st[j][i].score) ;
        sort(st[j],st[j] + k) ;
        int tmp = 0 ;
        for(int i = 0 ; i < k ; ++ i)
        {
            tmp = i ; while(tmp > 0 && st[j][tmp].score == st[j][tmp - 1].score) tmp -- ;
            st[j][i].local_rank = tmp + 1 ;
        }
        for(int i = 0 ; i < k ; ++ i) strcpy(student[cnt].name, st[j][i].name), student[cnt].score = st[j][i].score, student[cnt].local_rank = st[j][i].local_rank, student[cnt ++].location_number = j ;
    }
    sort(student, student + cnt) ;
    for(int i = 0, tmp ; i < cnt ; ++ i)
    {
        tmp = i ; while(tmp > 0 && student[tmp].score == student[tmp - 1].score) tmp -- ;
        student[i].final_rank = tmp + 1 ;
    }
    printf("%d
",cnt) ; for(int i = 0 ; i < cnt ; ++ i) printf("%s %d %d %d
",student[i].name,student[i].final_rank,student[i].location_number,student[i].local_rank) ;
    return 0;
}

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