运用object[key]相加值

let num = readline()

let line = ''
let arr = []
while( line = readline()){
    arr.push(line)
}

let tar = {}
for (let i = 0; i < arr.length; i++) {
    const element = arr[i];
    let childArr = element.split(' ')
    let key = childArr[0]
    let value = parseInt(childArr[1])
    if(tar[key]){
        tar[key] += value
    }else {
        tar[key] = value
    }
}

tar = tar.sort(function(a,b){ return a-b})

for (const key in tar) {
    if (Object.hasOwnProperty.call(tar, key)) {
        const element = tar[key];
        print(key + " " + element)
    }
}