题解 | #合并表记录#

const readline = require('readline');

const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
});

const lines = []
rl.on('line', function (line) {
    const tokens = line.split(' ');
    lines.push([parseInt(tokens[0]), parseInt(tokens[1])]);
});

rl.on('close', () => {
    const maps = lines.slice(1)
    const results = maps.reduce((prev, cur) => {
        const [index, value] = cur
        prev[index] =  prev[index] || 0
        prev[index] += value
        return prev
    }, {})

    const resultString = Object.entries(results).map(([key, value]) => `${key} ${value}`).join('\n')
    console.log(resultString)
})