题解 | #合并表记录#

#include <iostream>
#include <map>

int main() {
    int n;
    std::cin >> n;//读取输入的记录数量n
    std::map<int, int> table;  // Map to hold index and sum of values

    while (n--) {
        int index, value;
        std::cin >> index >> value;
        table[index] += value;  // Add value to the sum at the given index
    }

    // 自动按索引（键）排序
    for (const auto& entry : table) {
        if (entry.second > 0) {
            std::cout << entry.first << " " << entry.second << std::endl;
        }
    }

    return 0;
}