170. 两数之和 III - 数据结构设计

题意：

解题思路：

思路：
注意点：//4 - 2 = 2如果是本身，则跳过
if($target == $num && $cnt == 1) continue;

PHP代码实现：

class TwoSum {
    /**
     * Initialize your data structure here.
     */
    function __construct() {
        $this->map = [];
    }
    /**
     * Add the number to an internal data structure..
     * @param Integer $number
     * @return NULL
     */
    function add($number) {
        ++$this->map[$number];
    }
    /**
     * Find if there exists any pair of numbers which sum is equal to the value.
     * @param Integer $value
     * @return Boolean
     */
    function find($value) {
        foreach($this->map as $num => $cnt){
            $target = $value - $num;
            //4 - 2 = 2如果是本身，则跳过
            if($target == $num && $cnt == 1) continue;
            if(isset($this->map[$target])) return true;
        }
        return false;
    }
}

go代码实现：

type TwoSum struct {
    m map[int]int
}
/** Initialize your data structure here. */
func Constructor() TwoSum {
    return TwoSum{map[int]int{}}
}
/** Add the number to an internal data structure.. */
func (this *TwoSum) Add(number int)  {
    this.m[number]++
}
/** Find if there exists any pair of numbers which sum is equal to the value. */
func (this *TwoSum) Find(value int) bool {
    for n, c := range this.m {
        diff := value - n
        if n != diff {
            if c1 := this.m[diff]; c1 > 0 {
                return true
            }
        } else {
            //证明不是本身
            if c > 1 {return true}
        }
    }
    return false
}
/**
 * Your TwoSum object will be instantiated and called as such:
 * obj := Constructor();
 * obj.Add(number);
 * param_2 := obj.Find(value);
 */