Revise paste YOJ1195_1

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

// 检查4张牌中是否能找到两个不相交的集合，它们的点数和相等
// 返回 {取出的牌数, 点数总和}
pair<int, int> findBestSolution(vector<int>& cards) {
    int maxCards = 0;
    int maxSum = 0;
    
    // 枚举所有可能的子集组合
    for (int mask1 = 1; mask1 < 16; mask1++) {  // 从1到15，表示非空子集
        for (int mask2 = 1; mask2 < 16; mask2++) {
            // 两个集合不能有重叠
            if (mask1 & mask2) continue;
            
            int sum1 = 0, sum2 = 0;
            int cnt1 = 0, cnt2 = 0;
            
            // 计算第一个集合的点数和
            for (int i = 0; i < 4; i++) {
                if (mask1 & (1 << i)) {
                    sum1 += cards[i];
                    cnt1++;
                }
            }
            
            // 计算第二个集合的点数和
            for (int i = 0; i < 4; i++) {
                if (mask2 & (1 << i)) {
                    sum2 += cards[i];
                    cnt2++;
                }
            }
            
            // 检查点数和是否相等
            if (sum1 == sum2) {
                int totalCards = cnt1 + cnt2;
                int totalSum = sum1 + sum2;  // 或者 sum1 * 2
                
                // 优先选择牌数多的方案
                if (totalCards > maxCards) {
                    maxCards = totalCards;
                    maxSum = totalSum;
                }
                // 牌数相同时选择点数总和大的方案
                else if (totalCards == maxCards && totalSum > maxSum) {
                    maxSum = totalSum;
                }
            }
        }
    }
    
    return {maxCards, maxSum};
}

int main() {
    int n;
    cin >> n;
    
    vector<int> deck(n);
    for (int i = 0; i < n; i++) {
        cin >> deck[i];
    }
    
    // 反转牌堆，使其从栈顶到栈底（便于操作）
    reverse(deck.begin(), deck.end());
    
    int totalRemoved = 0;
    
    while (deck.size() >= 4) {
        // 取出栈顶的4张牌
        vector<int> currentCards;
        for (int i = 0; i < 4; i++) {
            currentCards.push_back(deck.back());
            deck.pop_back();
        }
        
        // 寻找最佳解决方案
        auto result = findBestSolution(currentCards);
        int cardsToRemove = result.first;
        
        // 如果没有找到解决方案，游戏结束
        if (cardsToRemove == 0) {
            break;
        }
        
        totalRemoved += cardsToRemove;
        
        // 标记要移除的牌
        vector<bool> removed(4, false);
        int bestMask1 = 0, bestMask2 = 0;
        int bestCards = 0, bestSum = 0;
        
        // 重新寻找最佳组合来标记要移除的牌
        for (int mask1 = 1; mask1 < 16; mask1++) {
            for (int mask2 = 1; mask2 < 16; mask2++) {
                if (mask1 & mask2) continue;
                
                int sum1 = 0, sum2 = 0;
                int cnt1 = 0, cnt2 = 0;
                
                for (int i = 0; i < 4; i++) {
                    if (mask1 & (1 << i)) {
                        sum1 += currentCards[i];
                        cnt1++;
                    }
                    if (mask2 & (1 << i)) {
                        sum2 += currentCards[i];
                        cnt2++;
                    }
                }
                
                if (sum1 == sum2) {
                    int totalCards = cnt1 + cnt2;
                    int totalSum = sum1 + sum2;
                    
                    if (totalCards > bestCards || 
                        (totalCards == bestCards && totalSum > bestSum)) {
                        bestCards = totalCards;
                        bestSum = totalSum;
                        bestMask1 = mask1;
                        bestMask2 = mask2;
                    }
                }
            }
        }
        
        // 标记要移除的牌
        for (int i = 0; i < 4; i++) {
            if ((bestMask1 & (1 << i)) || (bestMask2 & (1 << i))) {
                removed[i] = true;
            }
        }
        
        // 将未移除的牌按原顺序放回牌堆（从后往前放回）
        for (int i = 3; i >= 0; i--) {
            if (!removed[i]) {
                deck.push_back(currentCards[i]);
            }
        }
    }
    
    cout << totalRemoved << endl;
    
    return 0;
}