csp201912 题解

ccf题解 题解

1

//1805036   <13100928923>   <王恪楠>   报数  03-09 13:46 660B    C0X 正确  100 15ms    524.0KB
#include <bits/stdc++.h>
using namespace std;
queue<int> q;
int vis[50];
bool is_seven(int x)     //判断是否是需要跳过的数.
{
    if(x % 7 == 0)
        return 1;
    while(x){
        if(x % 10 == 7)
            return 1;
        x /= 10;
    }
    return 0;
}
int main()
{
    int n;
    scanf("%d", &n);
    q.push(1);        //用类似约瑟夫环的做法，循环报数.
    q.push(2);
    q.push(3);
    q.push(4);
    int cnt = 0, i = 0;
    while(cnt != n){
        i ++;
        int head = q.front();
        q.pop();
        q.push(head);
        if(is_seven(i)){
            vis[head] ++;
            continue;
        }
        cnt ++;
    }
    for(int i = 1; i <= 4; i ++)
        printf("%d\n", vis[i]);
    return 0;
}

2

//1805061   <13100928923>   <王恪楠>   回收站选址   03-09 14:06 1.352KB C0X 正确  100 15ms    848.0KB
#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
typedef pair<int, int> Pii;
vector<Pii> v;
map<Pii, int> vis;    //主要是用map记录下每个点是否有垃圾站.
int cnt[50];
int next_1[4][2] = {1, 0, -1, 0, 0, 1, 0, -1};
int next_2[4][2] = {1, 1, 1, -1, -1, 1, -1, -1};
inline int read()
{
    int res = 0, f = 1;
    char ch;
    ch = getchar();
    while(48 > ch || ch > 57){
        if(ch == '-')
            f = -1;
        ch = getchar();
    }
    while(48 <= ch && ch <= 57){
        res = (res << 3) + (res << 1) + ch - 48;
        ch = getchar();
    }
    return f * res;
}
int main()
{
    int n;
    n = read();
    for(int i = 1; i <= n; i ++){
        int tx, ty;
        tx = read(), ty = read();
        v.push_back(Pii(tx, ty));
        vis[Pii(tx, ty)] = 1;
    }
    for(int i = 0; i < v.size(); i ++){
        int x = v[i].fi, y = v[i].se;
        int flag = 0;
        for(int j = 0; j < 4; j ++){
            int tx = x + next_1[j][0], ty = y + next_1[j][1];
            if(!vis[Pii(tx, ty)])
                flag = 1;
        }
        if(flag)
            continue;
        int score = 0;
        for(int j = 0; j < 4; j ++){
            int tx = x + next_2[j][0], ty = y + next_2[j][1];
            if(vis[Pii(tx, ty)])
                score ++;
        }
        cnt[score] ++;
    }
    for(int i = 0; i < 5; i ++)
        printf("%d\n", cnt[i]);
    return 0;
}

3

#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
typedef pair<int, int> Pii;
map<string, int> vis;
vector<string> split(const string &s, const char &oprt)
{
    vector<string> res;
    string tmp;
    for(int i = 0; i < s.length(); i ++){
        if(s[i] != oprt)
            tmp += s[i];
        else{
            if(!tmp.empty())
                res.push_back(tmp);
            tmp.clear();
        }
    }
    if(!tmp.empty())
        res.push_back(tmp);
    return res;
}
Pii num(int start, const string &s)
{
    int res = 0;
    for(int i = start; i < s.length(); i ++){
        if(isdigit(s[i]))
            res = res * 10 + s[i] - 48;
        else
            return Pii(res, i - 1);
    }
}
void chemical_formula(string s, int flag)
{
    stack<string> s1, s2;
    map<string, int> vis0[50];
    int id = 0;
    for(int i = 0; i < s.length(); i ++){
        if(s[i] != ')'){
            string tmp = " ";
            tmp[0] = s[i];
            if(s[i] == '('){
                s1.push(tmp);
                id ++;
            }
            else{
                if('a' <= s[i + 1] && s[i + 1] <= 'z'){
                    tmp += s[i + 1];
                    i = i + 1;
                }
                if(isdigit(s[i + 1])){
                    Pii p = num(i + 1, s);
                    vis0[id][tmp] += flag * p.fi;
                    i = p.se;
                }
                else
                    vis0[id][tmp] += flag;
                s1.push(tmp);
            }
        }
        else{
            int tmp = 1;
            if(i + 1 < s.length() && isdigit(s[i + 1])){
                Pii p = num(i + 1, s);
                tmp = p.fi;
                i = p.se;
            }
            for(map<string, int> :: iterator it = vis0[id].begin(); it != vis0[id].end(); it ++){
                vis0[id - 1][it -> fi] += it -> se * tmp;
            }
            vis0[id].clear();
            id --;
        }
    }
    for(map<string, int> :: iterator it = vis0[id].begin(); it != vis0[id].end(); it ++)
        vis[it -> fi] += it -> se;
    return ;
}
void _find(string s0, int flag)
{
    vector<string> v = split(s0, '+');
    for(int i = 0; i < v.size(); i ++){
        string s = v[i];
        if(!isdigit(s[0]))
            chemical_formula("(" + s + ")", flag);
        else{
            int cnt = 0;
            for(int j = 0; j < s.length(); j ++){
                if(isdigit(s[j])){
                    cnt = cnt * 10 + s[j] - 48;
                }
                else{
                    s = s.substr(j);
                    break;
                }
            }
            chemical_formula("(" + s + ")", flag * cnt);
        }
    }
    return;
}
int main()
{
    int n;
    scanf("%d", &n);
    while(n --){
        string s;
        cin >> s;
        vis.clear();
        vector<string> v = split(s, '=');
        _find(v[0], 1);
        _find(v[1], -1);
        int flag = 0;
        for(map<string, int> :: iterator it = vis.begin(); it != vis.end(); it ++){
            if(it -> second)
                flag = 1;
        }
        if(!flag)
            printf("Y\n");
        else
            printf("N\n");
    }
    return 0;
}