CoderForces 479 div3 前五題

Wellcome to my csdn, Thank you !

This is CoderForces 479 div3.

The first one “Wrong Subtraction”

#include<cstdio>
#include<iostream>
#include<cstring>
#include<math.h>
#include<map>
#include<algorithm>
#include<string>
#include<set>
#include<vector>
typedef long long LL;
const LL N = 200000 + 5;
#define INF 10000000
#define min(a , b) ((a) < (b) ? (a) : (b))
#define lowbit(x) x&-x
using namespace std;
typedef long long ll;
const int maxn = int(2e5) + 7;
ll  k[maxn], sum[maxn], dmg;
LL a[maxn], ans;
vector<int>v[N];

int main() { //Test One
    int n, k;
    set<int>s;
    set<int>::iterator it;
    while (cin >> n >> k) {
        while (k--) {
            if (n == 0)break;
            if (n % 10)n--;
            else n /= 10;
        }
        cout << n << endl;
    }
}

The second one “Two-gram”

#include<cstdio>
#include<iostream>
#include<cstring>
#include<math.h>
#include<map>
#include<algorithm>
#include<string>
#include<set>
#include<vector>
typedef long long LL;
const LL N = 200000 + 5;
#define INF 10000000
#define min(a , b) ((a) < (b) ? (a) : (b))
#define lowbit(x) x&-x
using namespace std;
typedef long long ll;
const int maxn = int(2e5) + 7;
ll  k[maxn], sum[maxn], dmg;
LL a[maxn], ans;
vector<int>v[N];

int main() {//Test Two
    int n;
    cin >> n;
    char st[101];
    cin >> st;
    map<string, int>mp;
    map<int, string>ans;
    set<string>s;
    int a[101] = { 0 };
    int k = 0;
    int tt = 0;
    for (int i = 0; i < strlen(st) - 1; i++) {
        char t[3];
        t[0] = st[i];
        t[1] = st[i + 1];
        t[2] = '\0';
        s.insert(t);
        if (tt == s.size()) {
            a[mp[t]]++;
        }
        else
        {
            mp[t] = k;
            ans[k++] = t;
            a[mp[t]]++;
            tt = s.size();
        }
    }
    int max = 0;
    for (int i = 1; i < k; i++) {
        if (a[max] < a[i])max = i;
    }
    cout << ans[max] << endl;
    s.clear();
}

The third one “Less or Equal”

#include<cstdio>
#include<iostream>
#include<cstring>
#include<math.h>
#include<map>
#include<algorithm>
#include<string>
#include<set>
#include<vector>
typedef long long LL;
const LL N = 200000 + 5;
#define INF 10000000
#define min(a , b) ((a) < (b) ? (a) : (b))
#define lowbit(x) x&-x
using namespace std;
typedef long long ll;
const int maxn = int(2e5) + 7;
ll  k[maxn], sum[maxn], dmg;
LL a[maxn], ans;
vector<int>v[N];

int main() {//Test Three
    int n, k;
    while (cin >> n >> k) {
        for (int i = 0; i < n; i++) {
            scanf("%lld", &a[i]);
        }
        sort(a, a + n);
        if (k == 0) {
            if (a[0] == 1)
                cout << "-1\n";
            else cout << "1\n";
            continue;
        }
        //cout << a[k] << "  " << a[k - 1] << endl;
        if (a[k] == a[k - 1])cout << "-1\n";
        else cout << a[k - 1] << endl;
    }
}

The fourth one “Divide by three, multiply by two”

#include<cstdio>
#include<iostream>
#include<cstring>
#include<math.h>
#include<map>
#include<algorithm>
#include<string>
#include<set>
#include<vector>
typedef long long LL;
const LL N = 200000 + 5;
#define INF 10000000
#define min(a , b) ((a) < (b) ? (a) : (b))
#define lowbit(x) x&-x
using namespace std;
typedef long long ll;
const int maxn = int(2e5) + 7;
ll  k[maxn], sum[maxn], dmg;
LL a[maxn], ans;
vector<int>v[N];

int main() {//Test Four
    int n;
    while (cin >> n) {
        int tt[101] = { 0 };
        LL next[101] = { 0 };
        for (int i = 1; i <= n; i++) {
            cin >> a[i];
        }
        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= n; j++) {
                if (i == j)continue;
                if (a[i] * 2 == a[j] || a[i] == a[j] * 3) {
                    next[i] = j;
                    tt[j] = 1;
                }
            }
        }
        for (int i = 1; i <= n; i++) {
            if (!tt[i]) {
                while (i) {
                    cout << a[i] << " ";
                    i = next[i];
                }
                return 0;
            }
        }
        cout << endl;
    }
}

The fifth one “Cyclic Components”

#include<cstdio>
#include<iostream>
#include<cstring>
#include<math.h>
#include<map>
#include<algorithm>
#include<string>
#include<set>
#include<vector>
typedef long long LL;
const LL N = 200000 + 5;
#define INF 10000000
#define min(a , b) ((a) < (b) ? (a) : (b))
#define lowbit(x) x&-x
using namespace std;
typedef long long ll;
const int maxn = int(2e5) + 7;
ll  k[maxn], sum[maxn], dmg;
LL a[maxn], ans;
vector<int>v[N];

void dfs(int t) {
    a[t] = 1;
    if (v[t].size() != 2)ans = 0;
    for (int i = 0; i < v[t].size(); i++) {
        if (!a[v[t][i]])dfs(v[t][i]);
    }
}

int main() {//Test five
    ios::sync_with_stdio(false);
    int n, m;
    cin >> n >> m;
    memset(a, 0, sizeof(a));
    int s, e;
    for (int i = 0; i < m; i++) {
        cin >> s >> e;
        v[s].push_back(e);
        v[e].push_back(s);
    }
    int t = 0;
    for (int i = 0; i < n; i++) {
        if (!a[i]) {
            ans = 1;
            dfs(i);
            if (ans)t++;
        }
    }
    cout << t << endl;
}