如有侵权立即删除

7-1

#include <bits/stdc++.h>

using namespace std;

int main(){

//     freopen("data.in","r",stdin);
//     freopen("data.out","w",stdout);

    int n;

    int a = 0,b=1;

    cin >> n;

    int res = n;

    while(true)
    {
        if(a > n) break;
        if(abs(n - a) > abs(n - b)) res = b;
        else res = a;

        int t = a + b;
        a = b;
        b = t;
    }

    cout << res << endl;

    return 0;
}

7-2

#include <bits/stdc++.h>

using namespace std;

int main(){

//     freopen("data.in","r",stdin);
//     freopen("data.out","w",stdout);

    string s,t;

    cin >> s >> t;

    int n = s.size();
    int m = t.size();

    pair<int,int> res = {-1,-1};

    for(int i=0;i+m<=n;i++)
    {
        int p = 0,j=i;
        for(;j<n&&p<m;j++)
            if(t[p] == s[j])
                p ++ ;
        if(p == m)
        {
            if(res.first == -1 || res.second - res.first > j - i)
                res = {i,j};
        }
    }

    cout << s.substr(res.first,res.second-res.first) << endl;

    return 0;
}

7-3

#include <bits/stdc++.h>

using namespace std;

const int N = 1010;

int n;

string s[N];

int pre[N];

map<string,int> mp;
stack<int> stk;
int idx;
int d[N];

int work(string &s)
{
    int c = 0;
    reverse(s.begin(),s.end());
    while(s.size() > 0 && s.back() == ' ') 
    {
        s.pop_back();
        c++;
    }

    reverse(s.begin(),s.end());

    return c;
}

int main(){

//     freopen("data.in","r",stdin);
//     freopen("data.out","w",stdout);

    memset(pre,-1,sizeof pre);

    cin >> n;
    int last = -1;

    getline(cin,s[0]);

    for(int i=0;i<n;i++)
    {
        string str;
        getline(cin,str);

        int c = work(str);
        mp[str] = ++ idx;
        s[idx] = str;
        d[idx] = c;

        while(stk.size() > 0 && d[stk.top()] >= c)
            stk.pop();

        if(stk.size() > 0)
            pre[idx] = stk.top();
        stk.push(idx);
    }

    int T;

    cin >> T;

    while(T--)
    {
        string str; cin >> str;
        if(mp.count(str))
        {
            vector<string> res;
            int S = mp[str];
            while(S != -1)
            {
                res.push_back(s[S]);
                S = pre[S];
            }
            for(int i=res.size()-1;i>=0;i--)
            {
                if(i!=0) cout << res[i] << "->";
                else cout << res[i] << endl;
            }
        }
        else
        {
            printf("Error: %s is not found.\n",str.c_str());
        }

    }


    return 0;
}

7-4

#include <bits/stdc++.h>

using namespace std;

const int N = 110;

bool st[N];

vector<int> ver[N];

string equation[N];
vector<int> e[N];
int nd[N],m;

vector<int> res;

void dfs(int u)
{
    if(u == m)
    {
        for(auto x : res) 
        {
            cout << equation[x] << endl;
        }
        exit(0);
    }

    int t = nd[u];

    for(auto x : ver[t])
    {
        bool flag = true;
        for(auto y : e[x])
            if(!st[y])
                flag = false;
        if(flag)
        {
            for(auto y : e[x])
                st[y] = false;
            res.push_back(x);
            dfs(u + 1);
            res.pop_back();
            for(auto y : e[x])
                st[y] = true;
        }
    }
}

string get(int x)
{
    string s;
    if(x <= 9) s = "0" + to_string(x);
    else s = to_string(x);

    return s + " -> " + s;
}

bool CMP(int a,int b)
{
    return e[a] < e[b];
}

int main(){

//     freopen("data.in","r",stdin);
//     freopen("data.out","w",stdout);

    int n;

    cin >> n;

    for(int i=0;i<n;i++)
    {
        int x; cin >> x;
        st[x] = true;
    }

    cin >> m;

    for(int i=0;i<m;i++)
        cin >> nd[i];


    int k;

    cin >> k;

    string str;

    getline(cin,str);

    for(int i=0;i<k;i++)
    {
        getline(cin,str);
        stringstream ssin(str);
        string s;
        vector<int> v;
        while(ssin >> s)
        {
            if(isdigit(s[0]))
            {
                v.push_back(stoi(s));
            }
        }
        equation[i] = str;
        ver[v.back()].push_back(i);
        for(int j=0;j<v.size()-1;j++)
        {
            e[i].push_back(v[j]);
        }
    }
    for(int i=0;i<m;i++)
    {
        int x = nd[i];
        ver[x].push_back(i + k);
        e[i + k].push_back(x);
        equation[i + k] = get(x);
        sort(ver[nd[i]].begin(),ver[nd[i]].end(),CMP);
    }

    dfs(0);

    return 0;
}