第十四届蓝桥杯省赛C++C组C题【三国游戏】题解（AC）

解题思路

由于三种国家都有获胜的可能，所以我们需要分别枚举 X , Y , Z X,Y,Z X,Y,Z 获胜的情况。

设 X X X 获胜，那么对于第 i i i 个事件的贡献为 a [ i ] − ( b [ i ] + c [ i ] ) a[i]-(b[i]+c[i]) a[i]−(b[i]+c[i])，根据贪心的策略，我们可以考虑将所有时间按照贡献进行排序，贡献越大则优先选择。

Y , Z Y,Z Y,Z 获胜同理。

注意

X X X 的获胜条件为 X > Y + Z X > Y + Z X>Y+Z，非 X ≥ Y + Z X \geq Y + Z X≥Y+Z。
无获胜国时，输出 -1。

AC_Code

cpp 复制代码

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

using namespace std;

typedef long long LL;

const int N = 1e5 + 10;

int n;
int a[N], b[N], c[N], d[N];

int get(int a[], int b[], int c[])
{
    for (int i = 0; i < n; ++ i )
        d[i] = a[i] - b[i] - c[i];
    
    sort(d, d + n, greater<int>());
    
    LL res = 0;
    for (int i = 0; i < n; ++ i )
    {
        res += d[i];
        if (res <= 0)
            return i;
    }
    
    return n;
}

int main()
{
    cin >> n;
    for (int i = 0; i < n; ++ i )
        cin >> a[i];
    for (int i = 0; i < n; ++ i )
        cin >> b[i];
    for (int i = 0; i < n; ++ i )
        cin >> c[i];
    
    int res = max({get(a, b, c), get(b, a, c), get(c, a, b)});
    
    if (res == 0)
        res = -1;
    
    cout << res << endl;
    
    return 0;
}

cpp 复制代码

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

using namespace std;

typedef long long LL;

const int N = 1e5 + 10;

int n;
struct Node
{
    int x, y, z;
}q[N];

bool cmp_x(Node a, Node b)
{
    return a.x - a.y - a.z > b.x - b.y - b.z;
}

bool cmp_y(Node a, Node b)
{
    return a.y - a.x - a.z > b.y - b.x - b.z;
}

bool cmp_z(Node a, Node b)
{
    return a.z - a.x - a.y > b.z - b.x - b.y;
}

int main()
{
    cin >> n;
    for (int i = 0; i < n; ++ i )
        cin >> q[i].x;
    for (int i = 0; i < n; ++ i )
        cin >> q[i].y;
    for (int i = 0; i < n; ++ i )
        cin >> q[i].z;
    
    LL res = -1, sum = 0, t = 0;
    sort(q, q + n, cmp_x);
    for (int i = 0; i < n; ++ i )
    {
        sum += q[i].x - q[i].y - q[i].z;
        if (sum <= 0)
            break;
        t ++;
    }
    res = max(res, t);
    
    sum = 0, t = 0;
    sort(q, q + n, cmp_y);
    for (int i = 0; i < n; ++ i )
    {
        sum += q[i].y - q[i].x - q[i].z;
        if (sum <= 0)
            break;
        t ++;
    }
    res = max(res, t);
    
    sum = 0, t = 0;
    sort(q, q + n, cmp_z);
    for (int i = 0; i < n; ++ i )
    {
        sum += q[i].z - q[i].x - q[i].y;
        if (sum <= 0)
            break;
        t ++;
    }
    res = max(res, t);
    
    cout << (!res? -1: res) << endl;
    
    return 0;
}

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