大一寒假集训 stl&并查集

A - Let the Balloon Rise HDU - 1004   迭代器遍历 

题目大意：给一些气球颜色输出数量最多的气球颜色。

#include<iostream>
#include<cstdio>
#include<vector>
#include<map>
using namespace std;
const int maxn = 10000;
int main() {
    int n;
    while (scanf("%d", &n),n) {
        map<string, int>mp;
        char s[100];
        while (n--) {
            scanf("%s", s);
            if (mp.count(s) == 0)
                mp.insert(pair<string, int>(s, 1));
            else mp[s]++;
        }
        int max = 0;
        string str;
        for (map<string, int>::iterator it = mp.begin(); it != mp.end();++it)
        {
            if (it->second > max) {max = it->second;str = it->first;}
        }
        cout << str << endl;
    }
}

#include <iostream>
#include <map>
#include <string>
#include<algorithm>
using namespace std;
int main()
{
    //map<string, int> m;
    string s;
    string ans;
    int n;
    while (scanf("%d", &n), n) {
        int max = 0;
        map<string, int> m;
        while (n--)
        {
            cin >> s;
            if (m.find(s) == m.end())
            {
                m[s] = 1;
            }
            else
            {
                m[s]++;
            }

            if (m[s] > max) {
                max = m[s];
                ans = s;
            }
        }
        cout << ans << endl;
    }
    return 0;
}

B - 人见人爱A-B HDU - 2034 

#include <iostream>
#include <map>
#include <string>
#include<algorithm>
#include<vector>
#define maxn 110
using namespace std;
int main()
{
    int n, m;
    while (scanf("%d %d",&n,&m),n+m)
    {
        int t;
        vector<int>a,b,c;
        for (int i = 0;i < n;i++)
        {
            cin >> t;
            a.push_back(t);
        }
        for (int i = 0;i < m;i++)
        {
            cin >> t;
            b.push_back(t);
        }
        for (int i = 0;i < n;i++)
        {
            if (find(b.begin(), b.end(), a[i]) == b.end()) { c.push_back(a[i]); }
        }
        sort(c.begin(), c.end());
        if (c.begin() == c.end())printf("NULL");
        /*for (vector<int>::iterator it = c.begin();it != c.end();it++) {
            cout << *it << " ";
        }两种二选一*/
        for (int i = 0;i < c.size();i++) {
            cout << c[i] << " ";
        }
        printf("\n");
    }

}

C - 稳定排序 HDU - 1872    map排序

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<queue>
#include<map>
#include<vector>
#include<set>
#include<string>
#include<cmath>
#include<cstring>
#define INF 0x3f3f3f3f3f3f3f3f
using namespace std;
const int maxn = 310;
struct pe {
    string s;
    int score;
    int xu;
}per[maxn];
bool cmp(pe a, pe b) {
    if (a.score != b.score) return a.score > b.score;
    if (a.score == b.score && a.xu != b.xu)return a.xu < b.xu;
}
int main()
{
    int n;
    string ss;
    int grade;
    while (scanf("%d", &n) != EOF) {
        for (int i = 0;i < n;i++) {
            cin >> per[i].s >> per[i].score;
            per[i].xu = i;
        }
        sort(per, per + n, cmp);
        int flag = 1, fl = 1;//flag判断正确，fl判断稳定
        for (int i = 0;i < n;i++) {
            cin >> ss >> grade;
            if (grade != per[i].score) { flag = 0; }
            if (grade == per[i].score && ss != per[i].s) { fl = 0; }
        }
        if (flag == 1 && fl == 1) { printf("Right\n"); }
        else if (flag == 1 && fl == 0) {
            printf("Not Stable\n");
            for (int i = 0;i < n;i++) {
            cout << per[i].s << " " << per[i].score << "\n";
            }
        }
        else if (flag == 0) {
            printf("Error\n");
            for (int i = 0;i < n;i++) {
            cout << per[i].s << " " << per[i].score << "\n";
            }
        }
    }

}

D - 畅通工程 HDU - 1232 

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<queue>
#include<map>
#include<vector>
#include<set>
#include<string>
#include<cmath>
#include<cstring>
#define INF 0x3f3f3f3f3f3f3f3f
using namespace std;
const int maxn=1010;
int n, m;
int father[maxn];
void init(int n) {
    for (int i = 1;i <=n;i++) {
        father[i] = i;
    }
}
int find(int x) {
    return x == father[x] ? x : father[x] = find(father[x]);
}
void unite(int x, int y) {
    int fx = find(x);
    int fy = find(y);
    father[fx] = fy;
}
int main()
{
    while (scanf("%d %d", &n, &m), n) {
        init(n);
        int a, b;
        for (int i = 0;i < m;i++) {
            scanf("%d %d", &a, &b);
            unite(a, b);
        }
        int ans = 0;
        for (int i = 1;i <= n;i++) {
            for (int j = i + 1;j <= n;j++) {
                if (find(i) != find(j)) { ans++;unite(i, j); }
            }
        }
        printf("%d\n", ans);
    }
}

E - Wireless Network POJ - 2236   并查集

题目大意：O表示修复给出数字的电脑，S表示询问两台电脑之间是否联通。给出的数字为坐标。

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<queue>
#include<map>
#include<vector>
#include<set>
#include<string>
#include<cmath>
#include<cstring>
#define INF 0x3f3f3f3f3f3f3f3f
using namespace std;
const int maxn = 1010;
int father[maxn];
double dis[maxn][maxn];
int x[maxn], y[maxn], condition[maxn];
int N, d;
void init() {
    for (int i = 1;i <= maxn;i++) {
        father[i] = i;
    }
}
int find(int x) {
    return x == father[x] ? x : father[x] = find(father[x]);
}
void unite(int x, int y) {
    int fx = find(x);
    int fy = find(y);
    father[fx] = fy;
}
double distance(int x, int y, int x1, int y1) {
    return ((x - x1) * (x - x1) + (y - y1) * (y - y1));
}
int main()
{
    scanf("%d %d", &N, &d);
    for (int i = 1;i <= N;i++) {
        scanf("%d %d", x + i, y + i);
        condition[i] = 0;
    }
    for (int i = 1;i <= N;i++) {
        for (int j = i + 1;j <= N;j++) {
            dis[j][i] = dis[i][j] = distance(x[i], y[i], x[j], y[j]);
        }
    }
    init();
    char s[2];
    int num1, num2;
    while (~scanf("%s", s)) {
        if (s[0] == 'O') {
            scanf("%d", &num1);
            if (condition[num1] != 1) {
                condition[num1] = 1;
                for (int i = 1;i <= N;i++) {
                    if (condition[i] && dis[i][num1] <= d * d)
                    {
                        unite(num1, i);
                    }
                }
            }
            else continue;
        }
        else {
            scanf("%d %d", &num1, &num2);
            if (find(num1) == find(num2))printf("SUCCESS\n");
            else printf("FAIL\n");
        }
    }
    return 0;

}

F - How Many Tables HDU - 1213  

题目大意：不认识的人不坐一桌。最少要几桌。

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<queue>
#include<map>
#include<vector>
#include<set>
#include<string>
#include<cmath>
#include<cstring>
#define INF 0x3f3f3f3f3f3f3f3f
using namespace std;
const int maxn = 2000;
int father[maxn];
void init() {
    for (int i = 1;i <= maxn;i++) {
        father[i] = i;
    }
}
int find(int x) {
    return x == father[x] ? x : father[x] = find(father[x]);
}
void unite(int x, int y) {
    int fx = find(x);
    int fy = find(y);
    father[fx] = fy;
}
int main()
{
    int t;
    scanf("%d", &t);
    while (t--) {
        init();
        int n, m;
        scanf("%d %d", &n, &m);
        while (m--) {
            int a, b;
            scanf("%d %d", &a, &b);
            unite(a, b);
        }
        vector<int>v;
        for (int i = 1;i <= n;i++) {
            int res = find(i);
            if (find(v.begin(), v.end(), res) == v.end()) { v.push_back(res); }
        }
        printf("%d\n", v.size());
    }

}

G - 食物链 POJ - 1182 

#include<algorithm>
#include <iostream>
#include<cstdio>
using namespace std;
const int maxn = 150000 + 15;
int parent[maxn];
void init(int n) {
    for (int i = 0;i <n;i++) {
        parent[i] = i;
    }
}
int find(int x) {
    if (parent[x] == x)
        return x;
    else
        return parent[x] = find(parent[x]);
}
void unite(int x, int y) {
    y = find(y);
    x = find(x);
    parent[x] = y;

}
bool same(int x, int y) {
    return find(x) == find(y);
}
int n, k;
int main() {
    scanf("%d %d", &n, &k);
    init(n * 3);
    int d, x, y;
    int ans = 0;
    for (int i = 0;i < k;i++) {
        scanf("%d%d%d", &d, &x, &y);
        x = x - 1;y = y - 1;
        if ((x == y && d == 2) || x >= n || y >= n || x < 0 || y < 0) {//x和y相同不能建立捕食关系，x y超范围 
            ans++;
            continue;
        }
        if (d == 1) {
            if (same(x, y + n) || same(x, y + 2 * n))//x和y存在捕食关系 
                ans++;
            else {
                unite(x, y);
                unite(x + n, y + n);
                unite(x + 2 * n, y + 2 * n);
            }
        }
        else {
            if (find(x) == find(y) || find(x) == find(y + 2 * n))//x和y同级不能建立捕食关系，x和y存在相反的捕食关系 
                ans++;
            else {
                unite(x, y + n);
                unite(x + n, y + 2 * n);
                unite(x + 2 * n, y);
            }
        }
    }
    printf("%d\n", ans);
    return 0;
}

H - 看病要排队 HDU - 1873  优先队列

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<queue>
#include<map>
#include<vector>
#include<set>
#include<string>
#include<cmath>
#include<cstring>
#define INF 0x3f3f3f3f3f3f3f3f
using namespace std;
const int maxn = 1010;
struct patient {
    int id;
    int rank;
    friend bool operator<(patient a, patient b) {
        if (a.rank == b.rank)
            return a.id > b.id;
        else
            return a.rank < b.rank;
    }
}member, member1;
int main()
{
    int n;
    while (~scanf("%d", &n)) {
        int a, b;
        char s[10];
        int num;
        priority_queue<patient> q[5];
        int add = 0;
        while (n--) {
            scanf("%s", s);
            if (s[0] == 'I') {
                add++;
                cin >> a >> member.rank;
                member.id = add;
                q[a].push(member);
            }
            else {
                cin >> a;
                if (q[a].empty()) {
                    printf("EMPTY\n");
                }
                else {
                    member1 = q[a].top();
                    q[a].pop();
                    printf("%d\n", member1.id);
                }

            }
        }
    }
}