题解 | #合并表记录#

const readline = require("readline");

const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
});
let lines = [];
let res = [];
rl.on("line", function (line) {
    lines.push(line);
    if (lines.length - 1 == parseInt(lines[0])) {
        lines.shift(); //去掉第一个元素
        let newLines = lines.map((x) => x.split(" ").map(Number)); //split成新数组
        let res = newLines.reduce(
            (a, v) => ({
                ...a,
                [v[0]]: v[1] + (a[v[0]] = a[v[0]] ? a[v[0]] : 0),
            }),
            {}
        ); // reduce方法是关键，将array转化为Object
        for (const [key, value] of Object.entries(res)) {
            // 在Object中进行for循环
            console.log(`${key} ${value}`); // 按照输出规则打印每个元素
        }
    }
});