[C++知识库]第十届蓝桥杯C++B组省赛

后缀表达式

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

using namespace std;
const int N = 200010;
typedef long long LL;

int n, m;
int a[N];

int main()
{
    scanf("%d%d", &n, &m);
    int t = n + m + 1;
    for (int i = 0; i < t; i ++ ) scanf("%d", &a[i]);
    
    sort(a, a + t);
    
    LL sum = 0;
    if (!m)
    {
        for (int i = 0; i < t; i ++ ) sum += a[i];
    }
    else
    {
        sum = a[t - 1] - a[0];
        for (int i = 1; i < t - 1; i ++ ) sum += abs(a[i]);
    }
    cout << sum << endl;
    return 0;
}

灵能传输

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

typedef long long LL;

using namespace std;
const int N = 300010;

int n;
LL a[N], s[N];
bool st[N];

int main()
{
    int T;
    scanf("%d", &T);
    while (T -- ) // 出现循环考虑初始化
    {
        scanf("%d", &n);
        s[0] = 0; // 初始化
        for (int i = 1; i <= n; i ++ )
        {
            scanf("%lld", &a[i]);
            s[i] = s[i - 1] + a[i];
        }
        
        LL s0 = s[0], sn = s[n];
        if (s0 > sn) swap(s0, sn);
        sort(s, s + n + 1);
        
        for (int i = 0; i <= n; i ++ )
        {
            if (s[i] == s0)
            {
                s0 = i;
                break;
            }
        }
        
        for (int i = n; i >= 0; i -- )
        {
            if (s[i] == sn)
            {
                sn = i;
                break;
            }
        }
        
        memset(st, 0, sizeof st);
        int l = 0, r = n;
        for (int i = s0; i >= 0; i -= 2)
        {
            a[l ++ ] = s[i];
            st[i] = true;
        }
        
        for (int i = sn; i <= n; i += 2)
        {
            a[r -- ] = s[i];
            st[i] = true;
        }
        
        for (int i = 0; i <= n; i ++ )
            if (!st[i])
                a[l ++ ] = s[i];
        
        LL res = 0;
        for (int i = 1; i <= n; i ++ ) res = max(res, abs(a[i] - a[i - 1]));
        
        printf("%lld\n", res);
    }
    return 0;
}