1.

#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;

int n;

int main()
{
    cin >> n;
    int m = n;
    int cnt[3] =  {0}, cnt2[3] = {0};
    while(n -- ){
        int t, a, b;
        cin >> t >> a >> b;
        cnt[t] += a, cnt2[t] += b;
    }

    for(int i = 1;i <= 2;i ++ ){
        if(cnt[i] >= cnt2[i]) puts("LIVE");
        else puts("DEAD");
    }

    return 0;
}

2.简单贪心

#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;

string s;
int k;
int w[26];

int main()
{
    cin >> s;
    cin >> k;
    int maxv = 0;
    for(int i = 0;i < 26;i ++ ){
        cin >> w[i];
        maxv = max(maxv, w[i]);
    } 

    int n = s.size();
    int i = 1;
    long long res = 0;
    for(i = 1;i <= n;i ++ ){
        res += i * (w[s[i - 1] - 'a']);
    }

    while(k -- ){
        res += i * maxv;
        i ++ ;
    }
    cout << res << endl;

    return 0;

}

3.并查集

debug: 每倒入一种化学物质，如果该物质能够与之前倒入试管中的一种或多种物质发生反应，则试管的危险值将乘以 2。

#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>

using namespace std;

int n, m;

int p[51];
int cnt[51];

int find(int x)  // 并查集
{
    if (p[x] != x) p[x] = find(p[x]);
    return p[x];
}


int main()
{
    cin >> n >> m;
    for(int i = 1;i <= n;i ++ ) p[i] = i, cnt[i] = 1;

    int maxv = 1;
    while(m -- ){
        int x, y;
        cin >> x >> y;

        x = find(x), y = find(y);
        if(x != y){
            cnt[y] += cnt[x];
            p[x] = y;
        }
    }


    long long res = 1;
    for(int i = 1;i <= n;i ++ ){
        if(p[i] == i){
            while(-- cnt[i]){
                res *= 2;
            }
        }
    }
    cout << res << endl;


    return 0;
}