1 两数之和

    var num = [3,3];
    var target = 6;
    var twoSum = function(num, target) {
     var arr = [];
    //遍历数组
    for(var i = 0;i<num.length;i++){
     //每遍历完一个数接着计算下一个数与其他数的和
        for(var j =i+1;j<num.length;j++){
            //两两相加比较
            if(num[i]+num[j]==target){
     //将匹配的下标追加到数组中去
                arr.push(i,j);    
                break;
            }
        }
    }
    return arr;
};
var res=twoSum(num,target)
console.log(res);